Chapter 27. The Thoracic Spine

At the completion of this chapter,the reader will be able to:

1. Describe the vertebrae, ligaments, muscles, and blood and nerve supply that comprise the thoracic intervertebral segment.

2. Outline the coupled movements of the thoracic spine, the normal and abnormal joint barriers, and the responses of the various structures to loading.

3. Perform a detailed objective examination of the thoracic musculoskeletal system, including palpation of the articular and soft tissue structures, combined motion testing, position testing, passive articular mobility tests, and stability tests.

4. Evaluate the total examination data to establish the diagnosis and estimate the prognosis.

5. Describe the common pathologies and lesions of this region.

6. Apply manual techniques to the thoracic spine using the correct grade, direction, and duration.

7. Describe intervention strategies based on clinical findings and established goals.

8. Design an intervention plan based on patient education, manual therapy, and therapeutic exercise.

9. Evaluate intervention effectiveness in order to progress or modify an intervention.

10. Plan an effective home program, including spinal care and therapeutic exercise, and instruct the patient in this program.

The thoracic spine serves as a transitional zone between the lumbosacral region and the cervical spine. Despite the fact that the thoracic spine has not enjoyed the same attention as other regions of the spine in terms of research, it can be a significant source of local and referred pain. The thoracic spine is the most rigid region of the spine and, in this area, protection of the thoracic viscera takes precedence over segmental spinal mobility. In addition, the thorax is an important region of load transfer between the upper body (the head, cervical spine, and upper extremities) and the lower body (the lumbopelvic region and lower extremities).1,2

Because each thoracic vertebra is involved in at least six articulations, and as many as thirteen, establishing the specific cause of thoracic dysfunction involved may not always be possible. This task is made more difficult because of the inaccessibility of most of these joints.3

The thoracic spine (Fig. 27-1) forms a kyphotic curve between the lordotic curves of the cervical and lumbar spines. The curve begins at T1–2 and extends down to T12, with the T6–7 disk space as the apex.4 The thoracic kyphosis is a structural curve that is present from birth.5 Unlike the lumbar and cervical regions, which derive their curves from the corresponding differences in intervertebral disk (IVD) heights, the thoracic curve is maintained by the wedge-shaped vertebral bodies, which are about 2 mm higher posteriorly than anteriorly.

At the thoracolumbar junction, typically located between T11 and L1, the changes in curvature from one of kyphosis to one of lordosis vary quite widely according to posture, age, and previous compression fractures (see Chap. 5) and resulting deformity.6,7

The cervicothoracic junction anatomically comprises the C7–T1 segment and functionally includes the seventh cervical vertebra, the first two thoracic vertebrae, the first and second ribs, and the manubrium.

Thoracic Vertebra

The thoracic vertebrae consist of the usual elements: the vertebral body (centrum), transverse processes, and spinous process (Fig. 27-1).

Vertebral Body

The thoracic vertebral body (Fig. 27-1) is roughly as wide as it is long, so that its anteroposterior and mediolateral dimensions are of equal length.8 The anterior surface of the body is convex from side to side, whereas the posterior surface is deeply concave.8 The height, end-plate cross-sectional area, and bone mass of the vertebral bodies increase cranially to caudally, particularly in the lower levels.9,10 Progressive wedging of the thoracic vertebral bodies occurs with increasing age in the majority of individuals, with disk space narrowing at multiple levels occurring from the third decade of life.11 The vertebral bodies of most of the thoracic spine differ from those of the cervical and lumbar vertebrae because of the presence of a demifacet on each of their lateral aspects for articulation with the ribs (the costovertebral joint; see later discussion).

Intervertebral Disk

The IVDs of the thoracic spine have been poorly researched, although preliminary studies seem to indicate that the typical thoracic disk appears to have been adapted from a cervical design rather than from a lumbar design.12 The vertebral bodies of thoracic vertebrae 2–10 increase in size and change shape down the vertebral column, and, importantly, each has two demifacets for the attachment of ribs.12 The IVDs of this region are narrower and flatter than those in the cervical and lumbar spine and contribute approximately one-sixth of the length of the thoracic column.13 Disk size in the thoracic region gradually increases from superior to inferior. The disk height to body height ratio is 1:5, compared to 2:5 in the cervical spine, and 1:3 in the lumbar spine,14,15 making it the smallest ratio in the spine and affording the least amount of motion.16 Motion is further restricted by the orientation of the lamella of the annulus fibrosis (AF),17 and the relatively small nucleus pulposus (NP), which is more centrally located within the AF, and has a lower capacity to swell.18 The roughly circular cross-section of the thoracic disk allows the force of torsion to be evenly distributed around its circumference, making it better able to withstand these kinds of forces.19

In the thoracic spine, the segmental nerve roots are situated mainly behind the inferior–posterior aspect of the upper vertebral body rather than behind the disk, which reduces the possibility of root compression in impairments of the thoracic disk.20 In a review of 280 patients, Arce and Dohrmann21 found that thoracic disk herniation constitutes 0.25–0.75% of all disk herniations. Because the intervertebral foramina are quite large at these levels, osseous contact with the nerve roots is seldom encountered in the thoracic spine,20 and, as the dermatomes in this region have a fair amount of overlap, they cannot be relied upon to determine the specific nerve root involved.

In contrast to the cervical and lumbar regions, where the spinal canal is triangular/oval in cross-section and offers a large lateral excursion to the nerve roots, the mid-thoracic spinal canal is small and circular (Fig. 27-1), becoming triangular at the upper and lower levels. At the levels of T4–9, the canal is at its narrowest.20 The spinal canal is also restricted in its size by the pedicles, remaining within the confines of the vertebra and not diverging as they do in the cervical spine. This would tend to predispose the spinal cord to compression more than in the cervical spine, were it not for the smaller cord size and more oval shape of the thoracic canal. Despite this, central disk protrusions are more common in the thoracic region than in other regions of the spine, and, because the NP is small in the thorax, protrusions are invariably of the annular type, and nuclear protrusions are rare.20 Complicating matters is the fact that this is an area of poor vascular supply, receiving its blood from only one radicular artery. This renders the thoracic spinal cord extremely vulnerable to damage by extra dural masses or by an overzealous manipulation.

Transverse Processes

The transverse processes of the thoracic spine are oriented posteriorly (i.e., they point backward) and are located directly between the inferior articulating process and the superior articulating process of the zygapophyseal joints of each level (Fig. 27-1). This anatomical feature makes the transverse processes useful as palpation points, when performing mobility testing in the mid-thorax.

The transverse processes of the first 10 thoracic vertebrae differ from those of the cervical and lumbar spines because of the presence of a costal facet on the transverse process, which articulates with the corresponding rib to form the costotransverse joint (see later discussion). At the T11 and T12 levels, the costotransverse joint is absent because ribs 11 and 12 do not articulate with the transverse processes but rather with the vertebral body.

Spinous Processes

Two short and thick laminae come together to form the spinous process (Fig. 27-1). The spinous processes of the thoracic region are long, slender, and triangular shaped in cross-section. Although all of the thoracic spinous processes point obliquely downward, the degree of obliquity varies. The first three spinous processes, and the last three, are almost horizontal, whereas those of the mid-thorax are long and steeply inclined. T7 has the greatest spinous process angulation.

As elsewhere in the spine, the thoracic vertebrae are designed to endure and distribute the compressive forces produced by weight bearing, most of which is borne by the vertebral bodies. The compressive load at T1 is approximately 9% of body weight, increasing to 33% at T8 and 47 percent at T12.22,23

The thoracic vertebrae are classified as typical or atypical, with reference to their morphology. The typical thoracic vertebrae are found at T2–9, although T9 may be atypical in that its inferior costal facet is frequently absent. The atypical thoracic vertebrae are T1, T10, T11, and T12.

The first vertebra (T1) resembles C7. The centrum of T1 demonstrates a larger transverse than anteroposterior dimension of the vertebral body, being almost twice as wide as its length, and the spinous process is usually at least as long as that of C7. There are two ovoid facets on either side of the T1 vertebral body for articulation with the head of the first rib. The inferior aspect of the vertebral body of T1 is flat and contains a small facet at each posterolateral corner for articulation with the head of the second rib.

Approximately 32 structures attach to the first rib and body of T1.22,23 Because of the ring-like structure of the ribs, and their attachments both anteriorly and posteriorly, the thoracic spine and ribs can be viewed as a cage-like structure forming a series of concentric rings. Any movement occurring at the various joints of each ring (costovertebral, costotransverse, sternocostal, and zygapophyseal joints) has the potential to influence motions at the other joints within the ring, or at the neighboring segments.

The third vertebra is the smallest of the thoracic vertebra. The T9 vertebra may have no demifacets below, or it may have two demifacets on either side (in which case, the T10 vertebra will have demifacets only at the superior aspect). The T10 vertebra has one full rib facet located partly on the body of the vertebra and partly on the tubercle. It does not articulate with the 11th rib and so does not possess inferior demifacets, and occasionally there is no facet for the rib at the costotransverse joint.

The T11 and T12 segments form the thoracolumbar junction. The T11 vertebra has complete costal facets, but no facets on the transverse processes for the rib tubercle. The T12 vertebra only articulates with its own ribs and does not possess inferior demifacets.

Ligaments

The common spinal ligaments are present at the thoracic vertebrae (Fig. 27-2), and they perform much the same function as they do elsewhere in the spine. However, the anterior longitudinal ligament in this region is narrower but thicker compared with elsewhere in the spine,8 whereas the posterior longitudinal ligament is wider here at the level of the IVD, but narrower at the vertebral body than in the lumbar region.24

Zygapophyseal Joints

The zygapophyseal joints of the upper thoracic spine show some morphological features of the cervical region, and similarly the joints of the lower thoracic spine progressively approximate those of the upper lumbar region.25 The middle segments of the thoracic spine are designed for less mobility, as the thoracic cage articulations limit sagittal plane motion while accommodating axial displacements.25,26

The superior and inferior facets of the zygapophyseal joints arise from the upper and lower parts of the pedicle of the thoracic vertebra. The superior facet lies superiorly with the articular surface on the posterior aspect, whereas the inferior facet lies inferiorly with the articular surface on the anterior (ventral) aspect. The degree of superoinferior and mediolateral orientation is slight. The superior facet arises from near the lamina–pedicle junction and faces posteriorly, superiorly, and laterally.

The inferior articulating facet arises from the laminae to face anteriorly, inferiorly, and medially, lying posterior to the superior facet of the vertebra below. The facet surfaces are concave anteriorly and convex posteriorly, bringing the axis of rotation through the centrum rather than through the spinous process, as in the lumbar vertebrae. This results in the biomechanical center of rotation coinciding with the actual center of rotation formed by body weight.30

The zygapophyseal joints function to restrain the amount of flexion and anterior translation of the vertebral segment and to facilitate rotation.22 They appear to have little influence on the range of side bending.22

Ribs

The bony thoracic cage is formed by 12 pairs of ribs, the sternum, the clavicle, and the vertebrae of the thoracic spine (Fig. 27-1). The primary function of the rib cage is to protect the heart and lungs. All of the ribs of the cage are different from each other in size, width, and curvature, although they share some common characteristics. The first rib is the shortest. The rib length increases further inferiorly until the seventh rib, after which they become progressively shorter.

The ribs are divided into two classifications: true/false and typical/atypical.

• 1. True/false. Ribs 1–7 are named true ribs because their cartilage attaches directly to the sternum. The remaining ribs are false ribs, so named because their distal attachment is to the costochondral cartilage of their superior neighbor.
• 2. Typical/atypical. Ribs 3–9 are typical ribs. The first, ninth, 10th, 11th, and 12th ribs are considered atypical. The typical rib is characterized by a posterior end, which is composed of a head, neck, and tubercle. The head of the typical rib is characterized as two articular facets, a superior costal facet, and an inferior costal facet.
  • a. The superior facet attaches to the costal semilunar demifacet of the vertebra above its level.
  • b. The inferior facet attaches to the costal semicircular demifacet of the vertebra of the same level.12

The first, ninth, 10th, 11th, and 12th ribs are deemed atypical because they only articulate with their own vertebra via one full facet, and the lower two do not articulate with the costochondrium anteriorly.31

Typical Ribs

The head of the typical rib projects upward in a very similar manner to that of the uncinate process in the cervical spine and, in fact, develops in much the same way during childhood, appearing to play a similar mechanical role.8 The head consists of a slightly enlarged posterior end, which is divided by a horizontal ridge. The ridge serves as an attachment for the intra-articular ligament. The intra-articular ligament, which travels between the head of the rib and the IVD, bisects the joint into superior and inferior portions. Each of these portions normally contains a demifacet for articulation with the synovial costovertebral joints.

The tubercle of the typical rib lies on the outer surface, where the neck joins the shaft, and is more prominent in the upper parts than in the lower. The articular portion of the tubercle presents an oval facet for articulation at the costotransverse joint (Fig. 27-1).

The convex shaft of the rib is connected to the neck at the rib angle. The upper border of the shaft is round and blunt, whereas the inferior aspect is thin and sharp.8 The anterior end of the shaft has a small depression at the tip for articulation at the costochondral joint.

Atypical Ribs

The atypical first rib is small but massively built. Being the most curved and the most inferiorly orientated rib, it slopes sharply downward from its vertebral articulation to the manubrium. The head is small and rounded and articulates only with the T1 vertebra. The first costal cartilage is the shortest and this, together with the fibrous sternochondral joint (Fig. 27-1), contributes to the overall stability of the first ring of the rib cage. The first rib attaches to the manubrium just under the sternoclavicular joint, and the second rib articulates with the sternum at the manubriosternal junction. The atypical second rib is longer and is not as flat as the first rib. It attaches to the junction of the manubrium and the body of the sternum.

The atypical 10th rib has only a single facet on its head, because of its lack of articulation with the vertebra above. The 11th and 12th ribs do not present tubercles and have only a single articular facet on their heads. The 11th and 12th ribs remain unattached anteriorly, but end with a small piece of cartilage.

Attachment and Orientation of the Ribs

The attachment of the ribs to the sternum is variable (Fig. 27-1). The upper five, six, or seven ribs have their own cartilaginous connection (see “Sternocostal Joint” section).8 The cartilage of the eighth rib ends by blending with the seventh. The same situation pertains for the ninth and the 10th ribs, thus giving rise to a common band of cartilage and connective tissue.

The strong ligamentous attendance, and the presence of the two joints (costovertebral and costotransverse) at each level, severely limits the amount of movement permitted here to slight gliding and spinning motions, with morphology determining the function of each rib.

The orientation of the ribs increases from being horizontal at the upper levels to being more downwardly oblique in the inferior levels of the thoracic spine (a point worth remembering when performing palpation).

Costovertebral Joint

The thoracic vertebrae are connected to their adjacent vertebrae by the bilateral hyalinated, and synovial, costovertebral joints and their surrounding ligaments (see Fig. 27-1). The costovertebral articulation also forms an intimate relationship between the head of the rib and the lateral side of the vertebral body (see Fig. 27-1). The first, 11th, and 12th ribs articulate fully with their own vertebrae via a single costal facet, without any contact with the IVD, while the remaining ribs articulate with both their own vertebra and the vertebra above, as well as to the IVD. This could potentially predispose the first, 11th, and 12th costovertebral joints to early arthritic changes, as a result of more mechanical stress compared to the second to the 10th ribs.33

The radiate ligament connects the anterior aspect of the rib head to the bodies of two adjacent vertebrae and their intervening disk in a fanlike arrangement. Each of the three bands of the radiate ligament has different attachments:

1. The superior part runs from the head of the rib to the body of the superior vertebra.

2. The inferior part runs to the body of the inferior vertebra.

3. The intermediate part runs to the intervening disk.

Oda and colleagues34 reported that the costovertebral joint and rib cage confer stability on the thoracic spine. They performed symmetrically applied resections of the posterior elements first, followed by resection of the bilateral costovertebral joints and then complete obliteration of the rib cage. Their conclusion was that the thoracic spine may become unstable when the posterior elements and the bilateral costovertebral joints are obliterated. In addition, there is an increase in the neutral zone and range of motion in both side bending and rotation, indicating that these joints provide a stabilizing influence during coupled motions.34

Feiertag and colleagues35 reported that rib head joint resection showed significant increases in thoracic spinal motion in the sagittal and coronal planes. As the ossification of the head of the rib is not developed at the superior costovertebral joint until about age 13, younger individuals, such as gymnasts, can demonstrate a vast amount of thoracic rotation and side bending.

Costotransverse Joint

This is a synovial joint located between an articular facet on the posterior aspect of the rib tubercle and an articular facet on the anterior aspect of the transverse process, which is supported by a thin fibrous capsule (see Fig. 27-1). In the lower two thoracic vertebral segments, this articulation does not exist.

The neck of the rib lies along the entire length of the posterior aspect of the transverse process. The short and deep costotransverse ligament runs posteriorly from the posterior aspect of the rib neck to the anterior aspect of its transverse process, filling the costotransverse foramen that is formed between the rib neck and its adjacent transverse process. The ligament has two divisions:

1. The superior costotransverse ligament, also known as the interosseous ligament, or ligament of the neck of the rib, is formed in two layers. The anterior layer, which is continuous with the internal intercostal membrane laterally, runs from the neck of the rib up and laterally to the inferior aspect of the transverse process above. The posterior layer runs up and medially from the posterior aspect of the rib neck to the transverse process above.

2. The lateral costotransverse ligament runs from the tip of the transverse process laterally to the tubercle of its own rib. It is short, thick, and strong but is often damaged with direct blows to the chest (e.g., punch, kick, etc.).

Very little posteroanterior or anteromedial–posterolateral translation is available at this joint. Jiang and colleagues36 reported that the superior costotransverse ligaments are very important in maintaining the lateral stability of the spine.

Sternum

The sternum consists of three parts: the manubrium, the body, and the xiphoid process.

The manubrium (Fig. 27-1) is broad and thick superiorly and narrower and thinner inferiorly, where it articulates with the body. On either side of the suprasternal notch are articulating facets for the clavicles, and below these are the facets for the first rib. On the immediate inferolateral aspects of the manubrium are two more small facets for the cartilage of the second rib.

The articulation between the manubrium and the sternum is usually a symphysis, with the ends of the bones being lined with hyaline cartilage.

The body of the sternum is made up of the fused elements of four sternal bodies, and the vestiges of these are marked by three horizontal ridges. The upper end of the body articulates with the manubrium at the sternal angle. A facet at the superior end of the body laterally provides a joint surface common with the manubrium for the second costal cartilage. On each lateral border are four other notches that articulate with the third through sixth costal cartilages. The third rib has the deepest fossa on the sternum, indicating that it may serve as the axis for rotation and side bending during arm elevation. T7 articulates with both the sternum and the xiphoid.

The xiphisternum, or xiphoid process (see Fig. 27-1), is the smallest part of the sternum. It begins life in a cartilaginous state, but, in adulthood, the upper part ossifies.

A study37 examining the effect of removal of the entire sternum from the intact thorax found that its removal produced an almost complete loss of the stiffening effect of the thorax.

Sternocostal Joint

The first, sixth, and seventh costal cartilages are each linked to the sternum by a synchondrosis. The second to fifth ribs are each connected to the sternum through a synovial joint, whereby the cartilage of the corresponding rib articulates with a socket-like cavity in the sternum.38

In all of these joints, the periosteum of the sternum and the perichondrium of the costal cartilage are continuous. A thin fibrous capsule, present in the upper seven joints, attaches to the circumference of the articular surfaces, blending with the sternocostal ligaments. The surfaces of the joints are covered with fibrocartilage and are supported by capsular, radiate sternocostal, or xiphicostal and intra-articular ligaments. The joint is capable of about 2 degrees of motion from full inspiration to full expiration and allows the full excursion of the sternum in these activities.

Muscles

A large number of muscles arise from and insert on the thoracic spine and ribs (Fig. 27-2). The muscles of this region can be divided into those that are involved in spinal or extremity motion, and those that are involved in respiration (Tables 27-1 and 27-2).

Spinal and Extremity Muscles

Spinal Muscles

Iliocostalis Thoracis

The iliocostalis thoracis consists of several muscle straps that link the thoracic vertebrae and sacrum with the lower six or seven ribs. The muscle straps have a number of tendons, varying in different individuals, which insert in all angles in the lower six ribs. The function of the muscle is to extend the spine when working bilaterally and to side bend the spine ipsilaterally when working alone. The iliocostalis consists of three subdivisions—iliocostalis lumborum, iliocostalis thoracis, and iliocostalis cervicis—which are a part of the external portion of the long erector spinae muscle group. The muscle receives its nerve supply by the posterior (dorsal) rami of the thoracic nerves.

Longissimus Thoracis

The longissimus thoracis muscles originate with the intercostalis muscles from the transverse processes of the lower thoracic vertebrae. They insert into all of the ribs and into the ends of the transverse processes of the upper lumbar vertebrae. The function of the muscle is to extend the spine when working bilaterally and to side bend the spine ipsilaterally when working alone. The muscle is innervated by the posterior (dorsal) rami of the thoracic nerves.

Spinalis Thoracis

The spinalis thoracis muscle (spinalis dorsi) originates from the spinous processes of the upper lumbar and two lower thoracic vertebrae. It inserts in the spinous processes of the middle and upper thoracic vertebrae. The function of the muscle is to extend the spine. The muscle is innervated by the posterior (dorsal) rami of the thoracic nerves.

Semispinalis Thoracis

The semispinalis thoracis consists of long straps of muscle that stretch along and surround the vertebrae of the spine. The muscle can have between four and eight upper ends, which originate from the transverse processes of the T6–10. These straps of muscle insert in the spinous processes of the first four thoracic and fifth and seventh processes of C6–T4. The function of the muscle is to extend the spine when working bilaterally and to rotate the spine contralaterally when working alone. The semispinalis thoracis is innervated by the posterior (dorsal) rami of the thoracic nerves.

Multifidus

The multifidus is a deep back muscle that runs along the entire spine and lies deep to the erector spinae muscles. It originates from the sacrum, sacroiliac ligament, mammillary processes of the lumbar vertebrae, transverse processes of the thoracic vertebrae, and the articular processes of the last four cervical vertebrae. The multifidus consists of numerous bundles of fibers that cross over two to five vertebrae at a time and insert into the entire length of the spinous process above. The function of the muscle is to extend the spine when working bilaterally and to minimally rotate the spine contralaterally when working alone. The thoracic multifidus is innervated by the posterior (dorsal) rami of the thoracic spinal nerves.

Rotatores Thoracis (Longus and Brevis)

The rotatores muscles are deep spinal muscles that lie beneath the multifidus muscles. The rotatores brevis muscle lies just deep to the rotatores longus muscle. The rotatores muscles are the best developed in the thoracic region. There are a total of 11 small, quadrilateral rotatores muscles on each side of the spine. Each muscle arises from the transverse process of the vertebra and extends inward to the vertebra above. The rotatores muscles help rotate the appropriate thoracic segment. They are innervated by posterior (dorsal) rami of the thoracic spinal nerves.

Intertransversarii

The intratransversals are small muscles located between the transverse process of the vertebrae. In the thoracic region, they are single-bellied muscles and exist only from T10–11 to T12–L1. The function of the muscle is to ipsilaterally side bend the spine. The muscle is innervated by the posterior (dorsal) rami of the thoracic spinal nerves.

The other spinal muscles of the thoracic region act primarily on the cervical spine. These include the trapezius, levator scapulae, and anterior, posterior, and middle scalenes (see Chap. 25).

Extremity Muscles

The muscles of the thoracic region that act primarily on the extremities include the pectoralis major, latissimus dorsi, and serratus anterior (see Chap. 16).

Respiratory Muscles

The respiratory system is essentially a robust, multimuscle pump (Fig. 27-3). Connections to the respiratory mechanism have been found to exert a strong influence on such areas as the shoulder and pelvic girdles, as well as the head and neck. The primary task of the respiratory muscles is to displace the chest wall and, therefore, move gas in and out of the lungs to maintain arterial blood gas and pH homeostasis. The importance of normal respiratory muscle function can be appreciated by considering that respiratory muscle failure caused by fatigue, injury, or disease could result in an inability to maintain blood gas and pH levels within an acceptable range, which could have lethal consequences. Restoration of the respiratory mechanism is, thus, an essential element of thoracic intervention.

The actions of various respiratory muscles, which are broadly classified as inspiratory or expiratory, based on their mechanical actions, are highly redundant and provide several means by which air can be effectively displaced under a host of physiologic and pathophysiologic conditions.39,40

At rest, movement of air into and out of the lungs is the result of the recruitment of several muscles,41–43 and the expiratory phase of breathing at rest is also associated with active muscle participation.44 In a resting man, the tidal volume is the result of the coordinated recruitment of the diaphragm, the parasternal intercostal, and the scalene muscles (Tables 27-1 and 27-2).45,46

Although some have argued that the performance of the respiratory muscles does not limit exercise tolerance in normal healthy adults,47,48 heavy or prolonged exercise has been shown to impair respiratory muscle performance in humans.49,50 Thus, an interest in the adaptability of respiratory muscles to endurance-type exercise has grown significantly during the last decade.

The primary muscles of respiration include the diaphragm, the sternocostal, and the intercostals. The secondary muscles of respiration are the anterior/medial scalenes, serratus posterior, pectoralis major and minor, and, with the head fixed, the sternocleidomastoid.8

Diaphragm

Anatomically, the diaphragm muscle may be divided into sternal, costal, and lumbar parts:

• The sternal fibers originate from two slips at the back of the xiphoid process.
• The costal fibers originate from the lower six ribs and their costal cartilages.
• The lumbar fibers originate from the crura of the lumbar vertebra, and the medial and lateral arcuate ligaments.

Functionally and metabolically, the diaphragm can be classified as two muscles51,52:

1. The crural (posterior) portion that inserts into the lumbar vertebrae.

2. The costal portion that inserts into the xiphoid process of the sternum and into the margins of the lower ribs.

Thus, the muscle is attached around the thoracoabdominal junction circumferentially. From these attachments, the fibers arch toward each other centrally to form a large tendon. Contraction of the diaphragm pulls the large, central tendon inferiorly, producing diaphragmatic inspiration (see later discussion). The diaphragm has a phrenic C3–4 motor innervation and a sensory supply by the lower six intercostal nerves.

Intercostals

Between the ribs are the intercostal spaces, which are deeper both in front and between the upper ribs. Between the ribs lie the internal and external intercostal muscles, with the neurovascular bundle lying beneath each rib.

The intercostal muscles, together with the sternalis (or sternocostalis or transversalis thoracis), phylogenically form from the hypomeric muscles. These muscles correspond to their abdominal counterparts, with the sternalis being homologous to the rectus abdominis, and the intercostals homologous to the external oblique.8

External Intercostals

The external intercostal muscles (Fig. 27-2), of which there are 11, are laid in a direction that is superoposterior to inferoanterior (run inferiorly and medially in the front of the thorax and inferiorly and laterally in the back). Because of the oblique course of the fibers, and the fact that leverage is greatest on the lower of the two ribs, the muscle pulls the lower rib toward the upper rib, which results in inspiration. The external intercostals attach to the lower border of one rib and the upper border of the rib below, extending from the tubercle to the costal cartilage. Posteriorly, the muscle is continuous with the posterior fibers of the superior costotransverse ligament. The action of the external intercostals is believed to be entirely inspiratory,45 although the muscles also counteract the force of the diaphragm, preventing the collapse of the ribs.42 Innervation of this muscle is supplied by the adjacent intercostal nerve.

Internal Intercostals

The internal intercostals (see Fig. 27-2), which also number 11, have their fibers in an inferoposterior to a superoanterior direction. The internal intercostals are found deep to the external intercostals and run obliquely, and perpendicular, to the externals. The posterior fibers pull the upper rib down, but only during enforced expiration.42,45 The internal intercostals extend from the posterior rib angles to the sternum, where they end posteriorly. They are continuous with the internal membrane, which then becomes continuous with the anterior part of the superior costotransverse ligament. Innervation of this muscle group is supplied by the adjacent intercostal nerve.

Transverse Intercostals (Intima)

The deepest of the intercostals, the transverse intercostals are attached to the internal aspects of two contiguous ribs. They become progressively more significant, and developed, further down the thorax. This muscle is used during forced expiration.42,45

Transversus Thoracis

The transversus thoracis is a triangular-shaped sheet muscle, which originates from the posterior (dorsal) surface of the sternum and covers the inner surfaces of both the sternum and the second to eighth sternal costal cartilages. The apex of the muscle points cranially, with muscle slips running inferolaterally and eventually inserting on the sternal ribs quite close to the costochondral junctions. Morphologically, the transversus thoracis is similar to the anterior (ventral) part of the transversus abdominis. Its function is to draw the costal cartilages down. The muscle is innervated by the adjacent intercostal nerves.

Levator Costae

These consist of 12 strong short muscles that turn obliquely (inferolaterally), parallel with the external intercostals, from the tip of the transverse process to the angle of the rib, extending from C7 to T11 transverse processes. These muscles, which are innervated by the lateral branch of the posterior (dorsal) ramus of the thoracic nerve, function to raise the rib, but their importance in respiration is argued. The levator costae may also be segmentally involved in rotation and side bending of the thoracic vertebra.

Serratus Posterior Superior

The serratus posterior superior runs from the lower part of the ligamentum nuchae, the spinous processes of C7 and T1–3, and their supraspinous ligaments, to the inferior border of the second through fifth ribs, lateral to the rib angle.

The muscle receives its nerve supply from the second through fifth intercostal nerves. Its function is unclear, but it is thought to elevate the ribs.8

Serratus Posterior Inferior

This muscle arises from the spines and supraspinous ligaments of the two lower thoracic and the two or three upper lumbar vertebrae. It attaches to the inferior border of the lower four ribs, lateral to the rib angle.

The muscle receives its nerve supply from the anterior (ventral) rami of the ninth through 12th thoracic nerves. Its function is unclear, but it is thought to pull the ribs downward and backward.

Vascular Supply

The blood supply to this region is provided mainly by the posterior (dorsal) branches of the posterior intercostal arteries (Fig. 27-4), while the venous drainage occurs through the anterior and posterior venous plexuses. The spinal cord region between T4 and T9 is poorly vascularized.53

Neurology

The spinal canal in this region is narrow, with only a small epidural space between the cord and its osseous environment.53 Innervation of the thoracic spinal canal is by the sinuvertebral nerve, which arises from the nerve root and reenters the epidural space.

The thoracic spinal cord is unusually susceptible to injury because it occupies a greater percentage of the total cross-sectional area of its surrounding spinal canal than do the cervical or lumbar sections of the spinal cord, and the thoracic cord is tightly packed in the canal and easily injured by displaced fragments of bone or disk material.54 Furthermore, the blood supply of the mid-thoracic spinal cord is tenuous, and seemingly trivial injuries can disrupt the blood supply to a substantial portion of the thoracic cord and result in devastating neurologic deficits.55

In the thoracic region, there is great variability in the topography of the nerves and the structures that they serve.56 Typically, the spinal root arises from the lateral end of the spinal nerve but, in 25% of cases, the spinal root is made up of two parts that arise from the superior border of the spinal nerve.57 The thoracic spinal nerves are segmented into posterior (dorsal) primary and anterior (ventral) primary divisions (see Chap. 3). As elsewhere, the dermatomes of this region are considered to represent the cutaneous region innervated by one spinal nerve through both of its rami.58

The peripheral nerves, which travel through the thoracic spine and chest wall, include the posterior (dorsal) scapular, thoracodorsal, and long thoracic nerves (see Chap. 3).

Knowledge of the regional biomechanics of the thoracic spine and rib cage assists the clinician in the interpretation of active movement and motion palpation examination in relation to the patient's symptoms.59 The thoracic spinal segments possess the potential for a distinctive array of movements. Most of the understanding with regard to the biomechanics of the thoracic spine is based largely on the ex vivo studies of White,22 and Panjabi et al.,1,60 and a variety of ‘clinical models.’28,61 In addition, although normative ranges of spinal motion have been reported for the lumbar spine, no such reliable data exists for the thoracic region.62

It is widely recognized that the mechanical behavior of the spine is influenced by load.63 Axial load has been shown to increase motion segment stiffness and decrease mobility. In addition, due to the modifying influence of the cage-like structure of the ribs, which provide a significant degree of stability,36 and the kyphotic shape of the curve, the biomechanics of the thoracic spine is considerably different from those of the lumbar and cervical regions. The increased stability/reduced mobility of the thoracic segments has been reported to produce three primary affects23,64:

1. It influences the motions available in other spinal regions as well as the shoulder girdle.

2. It increases the potential for postural impairments.65

3. It provides an important weight-bearing mechanism for the vertebral column.66 The load-bearing capacity of the spine has been found to be up to three times greater with an intact rib cage.37,67

Other biomechanical studies have investigated the stabilizing effects of the individual components of the thoracic spine34,68:

• The IVD can be regarded as the most important stabilizer in the thoracic functional unit mechanics.
• The rib head joints serve as stabilizing structures to the human thoracic spine under flexion–extension, side bending, and axial rotation loading, and resection after diskectomy increases range of motion by approximately 80% under all loading modes.
• The lateral portion of the facet joints plays an important role in providing spinal stability.
• In the thoracic spine, total resection of the posterior ligamentous complex leads to an approximately 40% increase in range of motion under flexion–extension, side bending, and axial rotation loading.

Flexion

Flexion of the thoracic spine in weight bearing is initiated by the abdominal muscles and, in the absence of resistance, is continued by gravity, with the spinal erector muscles eccentrically controlling the descent. Flexion may also occur during bilateral scapular protraction.

There are about 4–5 degrees of flexion available at the upper thoracic levels, 6–8 degrees in the middle layers, and 9–15 degrees in the lower levels,22 giving an overall total range for thoracic flexion of 20–45 degrees.69 End-range flexion is resisted by the posterior half of annulus and by the impaction of the zygapophyseal joints.

According to Lee,29 flexion of the cervicothoracic region consists of an anterior rotation of the head of the rib and a superoanterior glide of the zygapophyseal joints, whereas extension and arm elevation in this region consists of a posterior sagittal rotation and posterior translation of the superior vertebra. This latter action pushes the superior aspect of the head of the rib posteriorly at the costovertebral joint, producing a posterior rotation of the rib (the anterior aspect travels superiorly, while the posterior aspect travels inferiorly).29

In the remainder of the thorax, flexion results from the superior facets (i.e., the inferior articular processes of the superior vertebra of the segment) gliding superiorly and anteriorly28 (Table 27-3). This motion at the zygapophyseal joint is accompanied by an anterior translation of the superior vertebra, and a slight distraction of the centrum. It seems likely that the anterior vertebral translation produces a similar motion in the ribs, with a superior glide occurring at the costotransverse joint. During this motion, the anterior aspects of the ribs approximate each other, while the posterior aspects separate.

Studies have shown that the thoracic zygapophyseal facets play an important role in stabilization of the thoracic spine during flexion loading.60,70

Extension

Extension of the thoracic spine is produced principally by the lumbar extensors and results in an inferior glide of the superior facet of the zygapophyseal joint (see Table 27-3). One to two degrees of extension is available at each thoracic segment, giving an overall average of 15–20 degrees of thoracic extension for the entire thoracic spine.

Extension of the thoracic spine is restrained by the relative stiffness of the anterior IVD; the anterior longitudinal ligament; bony contact of the posterior elements, including the inferior facet onto the lamina below; and the spinous processes.23,60 Given the location of the axis of rotation for extension, which is close to the moving segment, more translation than rotation occurs during extension.71

The joint motions occurring with extension are essentially the opposite of those of flexion. The translation of the vertebra occurs in a posterior direction, with an accompanying slight compression of the centra. The posterior translation that occurs with extension is controlled by the posteriorly directed lamellae of the annulus, and by the capsule of the zygapophyseal joint.

The transitional region between the thoracic and lumbar spines can produce an inflexion point that may serve to reduce the bending forces in the sagittal plane.6 However, stiffness in this area also may result in the thoracic spine pivoting over the thoracolumbar region, thereby increasing the risk of compression fracture (see Chap. 5).72

In addition to those motions occurring at the zygapophyseal joints and the vertebral body during thoracic extension, motion also occurs at the rib articulations. The ribs rotate posteriorly, with the posterior aspects approximating and the anterior aspects separating, and an inferior glide occurs at the costotransverse joint.29

Side Bending

Side bending of the thoracic spine is initiated by the ipsilateral abdominals and erector muscles, and then continued by gravity. A total of 25–45 degrees of side bending is available in the thoracic spine, at an average of about 3–4 degrees to each side per segment, with the lower segments averaging slightly more, at 7–9 degrees, each.22,73

At the zygapophyseal joints, the primary motion involves the ipsilateral superior facet gliding inferiorly, and the contralateral gliding superiorly (see Table 27-3). In effect, the ipsilateral zygapophyseal joint extends while the contralateral flexes. Side bending is restrained by the compression of the IVD and approximation of the ribs.

Side bending in the upper thoracic spine is associated with ipsilateral rotation and ipsilateral translation.74 According to Lee,29 the coupling that occurs in the rest of the thoracic spine depends on which of the two coupling motions initiates the movement. If side bending initiates the movement, it is called latexion, and the biomechanics consist of side bending, contralateral rotation, and ipsilateral translation. The mechanism of this coupling, or actually tripling, is not certain, and one must guard against strong conclusions. The postulated mechanism is as follows: with side bending, a contralateral convex curve is produced. This causes the ribs on the convex side of the curve to separate and those on the concave side to approximate.29 Trunk side bending is essentially halted, by soft tissue tension or rib approximation, or both, and the ribs become fixed. Further side bending is modified by the fixed ribs.29 The ipsilateral articular facet of the transverse process glides inferiorly on its rib, resulting in a relative anterior rotation of the neck of the rib, while the contralateral transverse process glides superiorly, producing a posterior rotation of the rib neck.29 The effect of these bilateral rib rotations is to force the superior vertebra into rotation away from the direction of side bending.

Rotation

The axis of rotation for the thoracic spine varies according to the vertebral level.75 The axis of rotation lies within the vertebral body in the mid-thoracic joints, but anterior to the vertebral body in the upper and lower joints.75 Almost pure rotation can occur in the mid-thoracic region, whereas, in the upper and lower segments, rotation can be associated with side bending to either side (see Table 27-3). Axial rotation (rotexion) is produced either by the abdominal muscles and other trunk rotators or by the unilateral elevation of the arm. Pure axial rotation (twisting) can only occur at two points in the spine: at the thoracolumbar and cervicothoracic junctions.

A total of 35–50 degrees of rotation is available in the thoracic spine.22,73 Segmental axial rotation in the thoracic spine averages 7 degrees in the upper thoracic area, approximately 5 degrees in the middle thoracic spine, and 2–3 degrees in the last two or three segments.22,69,76 Torsional stiffness is enhanced in the thoracolumbar region by the mortise-type morphology of the zygapophyseal joints and the near sagittal alignment of the upper lumbar articulations.23,27,66,72,77

According to MacConaill and Basmajian,30 thoracic segmental rotation is coupled with contralateral side bending and contralateral translation. However, this finding deviates from what is generally observed clinically, where the coupling of rotation and side bending that occurs seems to depend on the segmental level and the integrity of the joint.

Respiration

The ribs function as levers, with the fulcrum represented by the rib angle, the effort arm represented by the neck, and the load arm represented by the shaft. Because of the relatively small size of the rib neck, a small movement at the rib neck will produce a large degree of movement in the shaft.

The shapes of the articular facets of the upper six ribs would suggest that the upward and downward gliding movements that occur would produce spinning of the neck of the rib. In fact, the main movement in the upper six ribs during respiration and other movements is one of the rotations of the neck of the rib, with only small amounts of superior and inferior motion. In the seventh through 10th ribs, the principal movement is upward, backward, and medially during inspiration, with the reverse occurring during expiration.28

Because the anterior end of the ribs is lower than the posterior, when the ribs elevate, they rise upward, while the rib neck drops down. In the upper ribs, this results in an anterior elevation (pump handle) and in the middle and lower ribs (excluding the free ribs), a lateral elevation (bucket handle), with the former movement increasing the anteroposterior diameter of the thoracic cavity and the latter increasing the transverse diameter (Fig. 27-5).

Both kinds of rib motion are produced by the action of the diaphragm. The seventh through 10th ribs act to increase the abdominal cavity free space to afford space for the descending diaphragm. As the ends of these ribs are elevated, they push up on each other, lifting each successive rib upward and finally lifting the sternum. The two lower ribs are depressed by the quadratus lumborum to provide a stable base of action for the diaphragm.

Quiet respiration involves very little zygapophyseal joint motion.

Inspiration

During inspiration, the diaphragm descends and pulls the central tendon inferiorly through the fixed 12th ribs and L1–3 (Fig. 27-6). When the maximum extensibility (distention) of the abdominal wall is reached, the central tendon becomes stationary. Further contraction of the diaphragm produces an elevation and posterior rotation of the lower six ribs, with torsion of the anterior costal cartilage, and an anterosuperior thrust of the sternum (and eventually the inferior aspect of the manubrium).

During inspiration in the normal population, because the second rib is longer than the first, the superior aspect of the manubrium is forced to tilt posteriorly as its inferior edge is moved anteriorly. As the top of the manubrium tilts back, the clavicle rolls anteriorly. Because the lower ribs are longer, the inferior sternum moves further anteriorly than the superior section during inspiration. The manubriosternal junction acts as the hinge for this motion. If this joint stiffens or ossifies, respiratory function will suffer. In addition, if the central tendon stiffens, inspiration will have to be accomplished, with the ribs moving laterally.

Forced inspiration produces an increase in the activity level of the diaphragm, intercostals, scaleni, and quadratus lumborum. In addition, new activity occurs in the sternocleidomastoid, trapezius, both pectorals and serratus anterior.

During inspiration, the ribs move with the sternum in an upward and forward direction, increasing the anteroposterior diameter of the chest while posteriorly rotating. The tubercles and costotransverse joints of29

• T1–7 glide inferiorly;
• T8–10 glide in an anterolateral and inferior direction;
• T11 and T12 remain stationary, except for slight caliper motion increasing the lateral dimension.

Expiration

Quiet expiration occurs passively (Fig. 27-6). During forced expiration, there is activity in a number of muscles (Table 27-1). During expiration, the ribs rotate anteriorly and the tubercles and costotransverse joints of29

• T1–7 glide superiorly;
• T8–10 glide in a posteromedial and superior direction;
• T11 and T12 remain stationary, except for slight caliper motion decreasing the lateral dimension.

It may be possible to detect a subluxation of the costotransverse joints by palpating the ipsilateral transverse process and rib during inspiration and thoracic side bending.29 For example, a superior subluxation of the right rib may produce the following:

• A decreased inferior glide of the rib
• A decreased thoracic motion in the directions of left side bending and right rotation

The findings for other rib dysfunctions are outlined in Table 27-4.

Differential diagnosis of thoracic pain can be difficult. This is due to the complicated biomechanics and function of the region, the proximity to vital organs, and the many articulations. Bogduk78 has cited the following anatomical structures as possible causes of thoracic spine pain: posterior thoracic muscles, spinous processes, anterior and posterior longitudinal ligaments, vertebral bodies, zygapophyseal and costotransverse joints, inferior articular process, pars interarticularis, IVD, nerve root, joint meniscus, and dura mater. Pain arising from inflammation of the axial spine can mimic a variety of serious conditions, including cardiac/pulmonary pathology, renal colic, fracture, a tumor, or numerous visceral and retroperitoneal abnormalities, including abdominal aortic aneurysm.79

The thoracic spine is less commonly implicated in musculoskeletal pain syndromes than the lumbar and cervical spines, and when it does occur, there is some disagreement as to whether the ribs or the intervertebral joints are the major source of the biomechanical dysfunction. Complicating matters is the fact that pain arising from the thoracic spinal joints has considerable overlap and can refer symptoms to distal regions (groin, pubis, and lower abdominal wall) (refer to Chap. 5). Apart from musculoskeletal lesions, the thoracic spine is also a common source of systemic pain, and the phenomenon of referred pain poses more diagnostic difficulties in the thoracic spine than in any other region of the vertebral column (Fig. 27-7).78 The algorithm outlined in Fig. 27-8 can serve as a guide to the examination of the thoracic spine and ribs.

History

The history should include the chief complaints and a pain drawing. Referred chest pain patterns are outlined in Table 27-5. In addition to those questions listed under History in Chapter 4, the following questions should be asked by the clinician:

• Was there a mechanism of injury? Any information regarding the onset is important. For example, most rib injuries are commonly caused by direct trauma. If there was no mechanism of injury a disease process such as scoliosis could be indicated. Costovertebral and costotransverse joint hypomobility and active trigger points are possible sources of upper thoracic pain.80
• Do the symptoms occur with breathing? Symptoms reproduced with respiration could indicate a rib dysfunction or pleuritic pain. If the symptoms are aggravated on exertion, the clinician should focus on the relationship of specific movements or activities. Any information regarding the onset, as well as aggravating factors, is important, especially if the pain appears only during certain positions or movements, which would suggest a musculoskeletal lesion. Deep breathing or arm elevation tends to aggravate a rib dysfunction.
• Are the symptoms provoked or alleviated with movement or posture? This type of history indicates a musculoskeletal dysfunction. Chronic problems in this area tend to result from postural dysfunctions. Pain of a mechanical origin tends to worsen throughout the day but is relieved with rest.
• What activities tend to aggravate the symptoms? Pulling and pushing activities typically worsen thoracic symptoms. Aggravation of localized pain by coughing, sneezing, or deep inspiration tends to implicate the costovertebral joint.81
• Is the pain deep, superficial, aching, burning, or stabbing? The patient is asked to describe the quality of the pain. Thoracic nerve root pain is often sharp, stabbing, and severe, although it can also have a burning quality. Nerve pain usually is referred in a sloping band along an intercostal space.20 Vascular pain and visceral pain often are described as being poorly localized and achy. A sudden onset of pain related to trauma could indicate a fracture, muscle strain, or ligament sprain.

• Where is the pain located? The patient should be asked to point to the area of pain. If the patient has difficulty localizing the pain, the clinician should suspect referred pain as the source. If the symptoms appear to be referred to the upper or lower extremities, or the head and neck, further investigation is required.
• Are the symptoms related to digestion? Some visceral conditions such as ulcers, can be referred to T4-T6 posteriorly.

The administration of the Oswestry Low Back Disability Questionnaire (Table 5-2), Neck Disability Index (Table 5-3), and McGill Pain Questionnaire (Chap. 4) may be helpful in determining the quality of pain and its effect on function.82–84

Systems Review

Thoracic pain may originate from just about all of the viscera (Table 27-6; see also Chap. 5). Both visceral and somatic afferent nerves transmit pain messages from a peripheral stimulus and converge on the same projection neurons in the posterior (dorsal) horn. Visceral pain tends to be vague and dull and may be accompanied by nausea and sweating (see Chap. 5). To help differentiate between visceral pain and musculoskeletal pain, the clinician should focus on the relationship of specific movements or activities. A medical screening questionnaire for the thoracic spine and rib cage region is provided in Table 27-7.

The thoracolumbar outflow of the autonomic nervous system (see Chap. 3) has its location here. Stimulation of this outflow can lead to the presence of facilitated segments, and trophic changes in the skin of the periphery.85

Systemic illnesses, such as rheumatoid arthritis and malignancy, and conditions causing referred pain must be included in the differential diagnosis. Nonmusculoskeletal causes of thoracic pain (Table 27-8)86 include the following:

• Dissecting aortic aneurysm.
• Myocardial infarction.
• Intercostal neuralgia.
• Pleural irritation. When the tissues of an irritated pleura are stretched, chest pain can result. This pain can be increased by breathing, as well as by trunk movements, a situation that could lead the clinician to believe that the problem is musculoskeletal.
• Tumor.
• Acute thoracic disk herniation.
• Unstable or stable angina pectoris.
• Pericarditis.
• Pneumothorax.
• Pneumonia.
• Cholecystitis.
• Peptic ulcer.
• Pyelonephritis.
• Nephrolithiasis (kidney stones).

Questions should be asked with regard to bowel and bladder function; upper and lower extremity numbness, tingling, or weakness; and visual or balance disorders. These symptoms may indicate compromise to the spinal cord, cauda equina, or central nervous system.

Questions must also be asked about unexplained weight loss, fever, chills, and night pain. These symptoms often are associated with cancer or systemic disease, although night pain may just be because the patient has an increased, and fixed, kyphosis and needs a softer bed to accommodate the deformity.87

Tests and Measures

Observation

The patient should be suitably disrobed to expose as much of this region as is necessary. As a quick orientation to the relationship of the bony structures (Fig. 27-1), the clinician should confirm the following findings:

• The spine of the scapula is level with the spinous process of T3.
• The inferior angle of the scapula is in line with the spinous processes of T7–9.
• The medial border of the scapula is parallel with the spinal column and about 5 cm lateral to the spinous processes.
• The iliac crests are level and symmetric. One crest higher than the other could suggest a leg-length discrepancy, an iliac rotation, or both.
• The shoulder heights are level. A normal variant is that individuals carry their dominant shoulder slightly lower than the nondominant side.

The clinician also should evaluate the following:

• Smoothness of the thoracic curve. By running the palm of the hand down the midline of the patient's thoracic spine, the clinician can determine the smoothness of the curvature. Any areas of flatness could suggest a vertebral dysfunction such as an opening restriction (extended, rotated, and side flexed [ERS] lesion), whereas areas of relative increased curvature suggest a closing restriction (flexed, rotated, and side flexed [FRS] lesion); refer to Chapter 25.
• Degree of thoracic kyphosis. As elsewhere in the spine, posture has an important influence on the available range of motion of the neighboring joints. Conversely, changes in the lumbar posture, such as excessive lordosis, and changes in the cervical spine, such as those rendered by a forward head position, can affect the thoracic spine. An increased lumbar lordosis increases the stresses applied to the thoracolumbar junction, whereas a forward head increases the stresses at the cervicothoracic junction.

The thoracic spine adopts a natural kyphotic curve, which is an increased convexity of the thoracic vertebrae. Varying degrees of kyphosis can occur in the thoracic spine. It is known that the thoracic kyphosis increases with age,88 and in women more than men.89 The appearance of increased kyphosis in the young is typically postural, but could be the result of Scheuermann's disease, or ankylosing spondylitis.23,90 The degree of curvature of the spine also has been found to be diurnal, with a slight flattening of the thoracic kyphosis occurring overnight.91 Attempts to define the “normal” thoracic kyphosis have demonstrated considerable variation in the asymptomatic population,65,92 suggesting that any individual differences reflect normal variations rather than deviations.

It has been theorized by a number of authors93–98 that postural dysfunctions in this region create an imbalance between agonists and antagonists, producing adaptive shortening and weakness. It is likely that these changes are degenerative in nature, resulting from a change in IVD height. Disk height changes commonly are seen in the upper mid-thoracic segments99 and may result in an alteration of the kyphotic curve, with subsequent compensatory changes in load bearing and movement. These altered load-bearing patterns may result in a compression of the anterior aspect of the thoracic IVDs, and a stretching of the thoracic extensors and the middle and lower trapezius. The posterior ligaments also are lengthened. In addition, the kyphotic posture is associated with adaptive shortening of the anterior longitudinal ligament, the upper abdominals, and the anterior chest muscles. The common kyphotic deformities include100:

• Dowager's hump. This deformity is characterized by a severely kyphotic upper posterior (dorsal) region, which results from multiple anterior wedge compression fractures in several vertebrae of the middle to upper thoracic spine (see Chap. 5), usually caused by post menopausal osteoporosis or long-term corticosteroid therapy (specificity, 0.99).101
• Hump back. This deformity is a localized, sharp, posterior angulation, called gibbus, produced by an anterior wedging of one of the two thoracic vertebrae as a result of infection (tuberculosis), fracture, or congenital bony anomaly of the spine.90
• Round back. This deformity is characterized by decreased pelvic inclination and excessive kyphosis.
• Flat back. This deformity is characterized by decreased pelvic inclination, increased kyphosis, and a mobile thoracic spine.
• Pelvic heights. A significant leg-length discrepancy (greater than 1/2 inch) can alter the lateral curvature of the spine, resulting in compensation.
• Amount of lateral curvature of the thoracic spine. When observing the thoracic spine, it is important to note the morphologic latitude of the spinal curvature.102 Two terms, scoliosis and rotoscoliosis, are used to describe the lateral curvature of the spine. Scoliosis is the older term and refers to an abnormal side bending of the spine but gives no reference to the coupled rotation that also occurs. Rotoscoliosis is a more detailed definition, used to describe the curve of the spine by detailing how each vertebra is rotated and side flexed in relation to the vertebra below. For example, with a left lumbar convexity, the L5 vertebra would be found to be side flexed to the right and rotated to the left in relation to the sacrum. The same would be true with regard to the relation between L4 and L5. This rotation, toward the convexity, continues in small increments until the apex at L3. L2, which is above the apex, is right rotated and right side flexed in relation to L3. The small increments of right rotation continue up until the thoracic spine, where the side bending and rotation return to the neutral position. The currently accepted definition of scoliosis is a 10-degree lateral curvature measured radiographically (see Chap. 7), with vertebral rotation of the spine taken with the patient standing upright.103 This definition is based on the fact that a graph of lateral spinal curvature of the general population is a smooth exponential function in which the sharpest change in slope occurs at 10 degrees.104 Despite this reasonable approach to the definition of the disease state, it results in an extremely high prevalence of the disorder in the general population of 2–3%.105 Scoliosis can be found in four forms: static, sciatic, idiopathic, and psychogenic. The cause of the latter is self-explanatory.
  • Static. Static, or structural, scoliosis in adults may be caused by a leg-length difference, a hemivertebra, osteoporosis, osteomalacia, or compression fractures. If a platform under the heel of the shorter limb eases or even abolishes the symptoms while standing or on lumbar flexion or extension, a shoe lift is advised.106,107
  • Sciatic. The sight of a patient with a pelvic shift or list is relatively common in patients presenting with LBP. The sciatic, or nonstructural, lumbar scoliosis results from sciatic pain caused by a lumbar disk herniation and unilateral spasm of the back muscles. Sciatic scoliosis usually occurs with convexity to the symptomatic side of the herniated disk.108 The shift is thought to result from the body finding a position of comfort and protection, as a consequence of an irritation of a spinal nerve or its dural sleeve,108 although the neuronal mechanisms of sciatic scoliosis have not been well clarified. These postural changes cannot be relieved by voluntary efforts but usually disappear after alleviation of the sciatic pain.108 The extent of a scoliosis should be noted if it is thought to be contributing to the patient's symptoms and is occurring because of pain or dysfunction. An attempt should be made to manually correct the shift to ascertain whether this can be done painlessly. A compensatory shift or scoliosis is often easy and painless to correct.109,110
  • Idiopathic. The curve of an idiopathic scoliosis, present since childhood, differs from the tilt of the spine associated with recent IVD problems in that it is accompanied by a lower thoracic or lumbar rotation deformity.106 If this deformity is not obvious in the standing posture, it should become obvious during flexion, as it is manifested by the so-called razor back eminence of the thoracic cage.

Scoliosis is never normal, although most cases are idiopathic, manifesting in the preadolescent years.4,111 An abnormal lateral thoracic curve is described as being structural or functional, and can produce a fixed deformity or a changeable adaptation, respectively, with the rib hump occurring on the convex side of the curve. Persistent scoliosis during forward bending (Adam's sign) is indicative of a structural curve. Structural curves may be genetic, congenital, or idiopathic, producing a structural change to the bone and a loss of spinal flexibility. With a structural scoliosis, the vertebral bodies rotate toward the convexity of the curve, producing a distortion.112 The distortion in the thoracic spine is called a rib hump. The rotation of the vertebral bodies causes the spinous processes to deviate toward the concave side. The curvature results in an adaptive shortening of the intrinsic trunk muscles on the concave side and lengthening of the intrinsic muscles on the convex side.

The curve patterns are named according to the level of the apex of the curve. For example, a right thoracic curve has a convexity toward the right, and the apex of the curve is in the thoracic spine. There may be a number of curves spanning the thoracic and lumbar region, and the clinician should determine if the curvature is:

• Contributing to the patient's pain. Frequently, these curves can be asymptomatic. A slight lateral curve in the coronal plane is thought to result from right-hand dominance, or the presence of the aorta.113
• Nonstructural, in which case the patient is able to correct the curves relatively easily.
• Adaptive, resulting from poor posture, nerve root irritation, leg-length discrepancy, atrophy, or hip contracture.
• Chest wall shape. On the anterior aspect of the thoracic region, the clinician should look for evidence of deformity.
  • Barrel chest. In this deformity, a forward and upward projecting sternum increases the anteroposterior diameter. The barrel chest results in respiratory difficulty, stretching of the intercostal and anterior chest muscles, and adaptive shortening of the scapular adductor muscles.
  • Pigeon chest. In this deformity, a forward and downward projecting sternum increases the anteroposterior diameter. The pigeon chest results in a lengthening of the upper abdominal muscles and an adaptive shortening of the upper intercostal muscles.
  • Funnel chest. In this deformity, a posterior-projecting sternum occurs secondary to an outgrowth of the ribs.114 The funnel chest results in adaptive shortening of the upper abdominals, shoulder adductors, pectoralis minor, and intercostal muscles, and in lengthening of the thoracic extensors and middle and upper trapezius.
• Motion of the ribs during quiet breathing.
• Asymmetry in muscle bulk, prominence, or length. According to Sahrmann,115 shortness of the rectus abdominis results in anterior rib cage depression, shortness of the internal oblique results in an increase in the infrasternal angle, and shortness of the external oblique results in a decreased angle. Rotatores atrophy could suggest nerve palsy, whereas rotatores hypertonicity could suggest a segmental facilitation.97,116
• Any lesions, swellings, or scars on the back and chest. This is a common area for the characteristic lesion pattern of herpes zoster (shingles), which follows the course of the affected nerve (see Chap. 5).

Gait

The analysis of the patient's gait pattern can provide valuable information as to whether the condition originates in the spine or lower extremities, resulting in gross weakness of the muscles that affect gait90 (see Chap. 6). For example, a decreased arm swing during gait can indicate stiffness of the thoracic segments.

Palpation

The spinous processes of the thoracic vertebrae are readily palpated (see Fig. 27-1), because they are not covered by muscle or thick connective tissue.90 Palpation of the thoracic transverse processes is more difficult, however, due to their depth relative to the more superficial structures of the spine. The landmarks outlined in Table 27-9 may be helpful to determine the segmental level involved.

The spinous processes are long and slender and have varying degrees of caudal obliquity, which changes slightly throughout the kyphotic curvature of the thorax, increasing in caudal angulation to the level of T7 and then decreasing in caudal angulation below T9. Traditionally, palpation of this area has utilized the “rule of threes.”

Figure 27-9

The rule of threes has been widely accepted in orthopaedic and manual therapy texts, but until recently, never validated with research. Based on a pilot study to investigate the validity of the rule of threes of the thoracic spine, Geelhoed and colleagues,118 using five cadaver specimens, determined that the rule of threes was not an accurate predictor of the location of the transverse processes of the thoracic spine. The limitations of the study were the small sample size, the fact that measurements were only performed in the horizontal plane (prone position), and the fact that cadavers were used instead of live subjects, which could affect IVD height, and spinal alignment. In a separate study, Geelhoed et al.119 have proposed a new model for predicting the location of the transverse processes of the thoracic spine. This proposed method states that the location of the transverse processes of a thoracic vertebra can be found lateral to the most prominent aspect of the spinous process of the vertebra one level above.119

Surface landmarks can be used to locate the ribs. The first rib is located 45 degrees medially to the junction of the posterior scalene and trapezius. Palpation of the first rib during respiration can detect the presence of asymmetry. Palpation of the first rib can also be performed during testing of the active motions of cervical rotation and side bending in patients with suspected brachialgia (see Chap. 25).

The fifth rib passes directly under, or slightly inferior to, the male mammary nipples (see Fig. 27-10). To palpate the rib angles of the interscapular ribs, the shoulders are positioned in horizontal adduction. The rib angles of 3–10 can then be felt about 2–5 cm lateral to the spinous processes (Fig. 27-11).

When palpating anteriorly, on the sternum, a rib dysfunction will be highlighted by the presence of asymmetry and should be compared with the posterior findings. A prominent rib angle on the back and a depression of that rib at the sternum indicate a posterior subluxation, the reverse occurring in an anterior subluxation, whereas a rib that is prominent both anteriorly and posteriorly indicates a single rib torsion.

The transverse processes are roughly level with their own body. The costal cartilages of the second rib articulate with the junction between the sternum and manubrium (Fig. 27-1).

Palpation of the soft tissues of the region is important. The clinician should note the presence of any tenderness, temperature changes, and muscle spasm. A comparison should be made between the firmness and tenderness of the paravertebral muscles and their relationship from side to side.

Active Motion Testing

Active range-of-motion tests are used to determine the osteokinematic function of two adjacent thoracic vertebrae during active motions, to identify which joints are dysfunctional, as well as the specific direction of motion loss.120 Active range of motion initially is performed globally, looking for abnormalities, such as asymmetric limitations of motion. A specific examination is then performed on any region that appears to have either excessive or reduced motion. If the history indicated that the patient's symptoms were altered with repetitive motions or sustained positions, these movements and postures should be included. Various techniques are used to correctly assess each area of the thoracic spine.

Movement restriction of the upper thoracic spine may be secondary to pain or a result of adaptive shortening of connective tissue or muscle.3 Because of the relationship that the first two ribs share with the zygapophyseal joints as part of the manubrial ring, associated movement dysfunction of these ribs is common. Physiologic movement in the thoracic spine decreases with age. Mid-thoracic hypomobilities are the most common thoracic presentation,110 with the movement restrictions being more common in the sagittal and frontal planes, particularly extension and side bending.3 Most of the trunk rotation below the level of C2 occurs in the thoracic spine.

The clinician should look for capsular or noncapsular patterns of restriction, pain, or painful weakness (possible fracture or neoplasm). The capsular pattern of the thoracic spine appears to be symmetric limitation of rotation and side bending, extension loss, and least loss of flexion. Joint capsular lesions demonstrate a capsular pattern as equal and grossly severe limitation of movement in every direction.90 With an asymmetric impairment, such as trauma, the capsular pattern appears to be an asymmetric limitation of rotation and side bending, extension loss, and a lesser loss of flexion.

Overpressure applied at the end of the available range of motion is used to take the joint from its physiologic barrier to its anatomic barrier. During overpressure, an increase in resistance to motion should be felt. The end-feels should be noted.

• If the normal elastic end-feel of thoracic rotation is replaced by a stiffer one, it may indicate the presence of osteoporosis or ankylosing spondylitis.
• During forward flexion, the nonstructural scoliosis disappears, whereas the structural scoliosis does not.
• If side bending is more seriously affected than rotation, neoplastic disease of the viscera or chest wall may be present.87
• If, during side bending, the ipsilateral paraspinal muscles demonstrate a contracture (Forestier's bowstring sign), ankylosing spondylitis may be present.121
• Side bending away from the painful side, which is the only painful and limited movement, almost always indicates a severe extra-articular impairment, such as a pulmonary or abdominal tumor or a spinal neurofibroma. The functional examination normally confirms the patient history.
• A marked restriction of motion in a noncapsular pattern with one or more spasmodic end-feels could indicate a thoracic disk herniation.
• Anterior or lateral pain with resisted thoracic rotation could indicate a muscle tear. Localized pain with resisted testing could indicate a rib fracture.

Because of the length of the spine in this region, it is important to ensure that all parts of the thoracic spine are involved in the range-of-motion testing. Motion in the thoracic spine requires a synchronous movement between the intervertebral and zygapophyseal joints and the rib articulations. Thus, the presence of joint dysfunction or degeneration, or structural changes in the spinal curvature, will influence the amount of available range of motion, and the pattern of these coupled motions.23

The inclinometer techniques recommended by the American Medical Association are used to objectively measure thoracic motion.122

Flexion

To measure thoracic flexion, two inclinometers are used and are aligned in the sagittal plane. The center of the first inclinometer is placed over the T1 spinous process. The center of the second one is placed over the T12 spinous process. The patient is asked to slump forward as though trying to place the forehead on the knees, and both inclinometer angles are recorded. The thoracic flexion angle is calculated by subtracting the T12 from the T1 inclinometer angle. The patient should be able to flex approximately 20–45 degrees.69,120 The clinician observes for any paravertebral fullness during flexion, which might indicate hypertonus from a facilitated segment. The thoracic spine during flexion should curve forward in a smooth and even manner (Fig. 27-10). There should be no evidence of segmental rotation or side bending. To decrease pelvic and hip movements, McKenzie advocates examining thoracic flexion with the patient seated.123

Extension

The clinician places one hand and arm across the upper chest region of the patient and the other hand over the spinous processes of the lower thoracic spine. The patient is guided into a backward slump (Fig. 27-11). Overpressure is applied by the arm across the front of the patient, while avoiding any anterior translation occurring at the lumbar spine.

Clinical guidelines for measurements of thoracic extension recommend that range of motion be defined with reference to the magnitude of the kyphosis measured in standing. However, to date, the relationship between the magnitude of the thoracic kyphosis and the amount of thoracic extension movement has not been reported.62 Thoracic extension may be measured using the same technique and inclinometer positions as described for flexion. The thoracic extension angle is calculated by subtracting the T12 from the T1 inclinometer angle. The patient should be able to extend approximately 15–20 degrees.120 Alternatively, thoracic extension can be measured using a tape measure. The distance between two points (the C7 and T12 spinous processes) is measured. A 2.5-cm difference between neutral and extension measurements is considered normal.121,124 During thoracic extension, the thoracic curve should curve backward or straighten. As with flexion, there should be no evidence of segmental rotation or side bending.

Rotation

The patient is seated and is asked to turn to each side at the waist. Overpressure is applied through both shoulders (Fig. 27-12). This motion tests the ability of the ribs and the superior vertebrae to translate in the direction opposite to the rotation—a motion that is essential if complete rotation and side bending is to occur. A total of 35–50 degrees of rotation is available in the thoracic spine.22,73 Rotation is a primary movement of the thoracic spine and a key component of functional activities. Active thoracic rotation of 20 degrees or less results in an impairment of function during activities of daily living involving the thoracic spine.121 Pavelka125 devised a simple objective clinical method to measure thoracolumbar rotation using a tape measure that can be used to detect asymmetries in rotation. The tape is placed over the L5 spinous process, wrapped around the trunk, and placed over the jugular notch on the superior aspect of the manubrium. A measurement is taken before and after full trunk rotation. The measurements from each side are then compared.

Side Bending

A total of 25–45 degrees of side bending is available in the thoracic spine.22,73 Using a hand placed against the patient's side, the patient is asked to side bend over the clinician's hand. Overpressure is applied through the contralateral shoulder to avoid compression (Fig. 27-13). Side bending can be measured objectively using a tape measure.126 Two ink marks are placed on the skin of the lateral trunk. The upper mark is made at a point where a horizontal line through the xiphisternum crosses the coronal line. The lower mark is made at the highest point on the iliac crest. The distance between the two marks is measured in centimeters, with the patient standing erect, and again after full ipsilateral side bending. The second measurement is subtracted from the first and the remainder is taken as an index of lateral spinal mobility.

Inspiration and Expiration

Using a tape measure, the clinician measures the amount of rib expansion that occurs with a deep breath. Respiratory excursion is measured at three levels, using a tape measure placed circumferentially around the chest at the level of the axilla, the xiphoid level, and the 10th rib level. Comparisons are made between the measurements taken at the position of maximum expiration and the measurement taken at full inspiration. The normal difference between inspiration and expiration is 3–7.5 cm (1–3 inches).126 Ankylosing spondylitis is a disease that can include ossification of the anterior longitudinal ligament, the thoracic disk, and the thoracic zygapophyseal joints. Findings of ankylosing spondylitis are common in the thoracic region, making chest expansion measurements a requirement in this region. Decreased expansion can highlight the presence of ankylosing spondylitis but may also be the result of diaphragm palsy (C4), intercostal weakness, pulmonary (pleura) problems, old age, a rib fracture, or a chronic lung condition.

The motions of the ribs are palpated during breathing. If a rib stops moving in relation to the other ribs on the same side during inspiration, it is classified as a depressed rib.117,127 If a rib stops moving in relation to the other ribs during expiration, it is classified as an elevated rib.117,127 Because of the interrelationship of all of the ribs, if a depressed rib is implicated, it is usually the most superior depressed rib that causes the most significant dysfunction. In contrast, if an elevated rib is implicated, it is usually the most inferior restricted rib that causes the most significant dysfunction.117,127

Resisted Testing

Resistance applied at the point of overpressure can give the clinician an indication of the integrity of the musculotendinous units of this area. Resistance is applied at the end range of flexion, extension, rotation, and side bending, while the clinician looks for pain, weakness, or painful weakness. Pain that is exacerbated with motion, but not with resisted isometric contraction, suggests a ligamentous lesion.120

Static Postural Testing

Thoracic pain of a postural origin is difficult to provoke with active motion and resistive testing. McKenzie123 recommends placing the patient in a position for approximately 3 minutes to load the structures sufficiently to provoke postural pain.

Differing Philosophies

The next stage in the examination process depends on the clinician's background. For clinicians who are heavily influenced by the muscle energy techniques of the osteopaths, position testing is used to determine the segment on which to focus. Other clinicians omit the position tests and proceed to the combined motion and passive physiologic tests.

Position Testing: Spinal

The vertebrae may be tested for positional symmetry. If an ERS or FRS is present, passive mobility testing will definitively diagnose the movement impairment. The upper thoracic joints (C7–T4) can be assessed using the cervical techniques described in Chapter 25. The following techniques can be used for the T4–12 levels.

Example: T6–7

The patient is positioned in sitting, with the clinician standing behind. Using one thumb, the clinician palpates the transverse process of the T6 vertebrae. Using the other thumb, the clinician palpates the transverse process of the T7 vertebrae (Fig. 27-14). The joint is tested in the following manner:

• The patient bends forward so that the joint complex is flexed, and an evaluation is made as to the position of the T6 vertebra relative to T7 by noting which transverse process is the most posterior. A posterior left transverse process of T6 relative to T7 is indicative of a left-rotated position of the T6–7 complex in flexion.
• The patient bends backward so that the joint complex is extended, and an evaluation is made as to the position of the T6 vertebra in relation to T7 by noting which transverse process is the most posterior. A posterior left transverse process of T6 relative to T7 is indicative of a left-rotated position of the T6–7 joint complex in extension.

Once a segment has been localized by one of the preceding techniques, the arthrokinematics of the segment can be tested using the following passive mobility tests, which incorporate specific symmetric or asymmetric motions. Care in the interpretation of the passive mobility tests is important, because local tenderness in the thoracic region is common, especially over the spinous processes as a result of the proximity of the posterior (dorsal) rami over the apex of these bony prominences.23,128

Combined Motion Testing

As normal function involves complex and combined motions of the thoracic spine, combined motion testing can also be used. The motions tested include forward flexion with side bending, extension with side bending, side bending with flexion, and side bending with extension. The results from these motions are combined with the findings from the history and the single plane motions to categorize the symptomatic responses. This information can guide the clinician when determining which motions to use in the intervention.

Passive Physiologic Mobility Testing

The upper thoracic zygapophyseal joints (C7–T4) can be assessed using the cervical techniques described in Chapter 25. The following techniques can be used for the T4–12 levels.

Flexion of the Zygapophyseal Joints. The patient is seated at the end of the table, with arms together and hands resting on the back of the head. The clinician stands by the side of the patient and reaches around the front of the patient with one arm and hand. The clinician then applies a slight pressure with the sternum against the patient's shoulder so that the patient is gently squeezed. Using the other hand to monitor intersegmental motion between the spinous processes (Fig. 27-15), the clinician flexes the thoracic spine (Fig. 27-15). The quantity and quality of motion are noted and compared with the levels above and below.

Extension of the Zygapophyseal Joints. The patient is seated with the arms together and both hands behind the head. The clinician stands to the side of the patient. While palpating the interspinous spaces or the transverse processes of the level to be tested with one hand, the clinician wraps the other arm around the front of the patient and rests that hand on the patient's contralateral elbow (Fig. 27-16). Crouching slightly, the clinician then places his or her anterior shoulder region close to the lateral aspect of the patient's shoulder. Using the other hand to monitor inter-segmental motion between the spinous processes, the clinician extends the thoracic spine (Fig. 27-16). The quantity and quality of motion is noted and compared with the levels above and below.

Combined Motions of the Zygapophyseal Joints. The patient is seated with one hand on top of one of the shoulders and the other hand under the opposite axilla. The clinician stands to the side of the patient. While palpating the interspinous spaces or the transverse processes of each level with one hand, the clinician wraps the other arm around the front of the patient, under the patient's crossed arms, resting his or her hand on the patient's contralateral hand. Crouching slightly, the clinician then places the anterior shoulder region against the lateral aspect of the patient's shoulder. Side bending and rotation of the patient's thoracic spine is then performed away from the clinician (Fig. 27-17), as the clinician lifts with his or her body. The palpating hand palpates the concave side of the curve.

Passive Articular Mobility Testing of the Mid-Thoracic Spine

Under normal circumstances, if the active motions and passive mobility motions of a joint are found to be restricted, the arthrokinematics of the restricted motion(s) are assessed to determine if the hypomobility is articular or extra-articular (myofascial). However, given the number of joints at each segmental level and the proximity of many of them, it is unlikely that passive articular mobility testing in this region will yield any useful information.

Neurologic Tests

A neurologic deficit is very difficult to detect in the thoracic spine. In this region, one dermatome may be absent with no loss of sensation.129 Several tests have been devised to help assess the integrity of the neurologic system in this area.

The Slump Test

A neurodynamic mobility test can be used as a general assessment (see Chap. 11).

Sensory Testing

Sensation should be tested over the abdomen. The area just below the xiphoid process is innervated by T8, the umbilicus by T10, and the lower abdominal region, level with the anterior superior iliac spines, by T12.87 Too much overlap exists above T8 to make sensation testing reliable.

Pathological Reflexes

Because of the proximity and vulnerability of the spinal cord in this region, long tract signs (Babinski, Oppenheim, clonus, and muscle stretch [deep tendon] reflexes) should be routinely assessed.

Lhermitte's Symptom

This impairment usually is considered to be a lesion to the cervical spinal cord (see Chap. 3), and it is associated with demyelination, prolapsed cervical disk, neck trauma, or subacute combined degeneration of the cord. Because the thoracic cord is immobilized by the denticulate ligaments, flexion will produce only limited stretching of the cord and thus less excursion. Lhermitte's symptom, characterized by an electric shock-like sensation into the spinal cord and limbs during neck flexion, may be present in the thoracic spine with compression of the thoracic cord by metastatic malignant deposits,130 impairments of the thoracic vertebrae,131 and thoracic spinal tumors.132

Brown–Séquard Syndrome

This syndrome is characterized by ipsilateral flaccid segmental palsy, ipsilateral spastic palsy below the impairment, and ipsilateral anesthesia, loss of proprioception, and loss of appreciation of the vibration of a tuning fork (dysesthesia). Contralateral discrimination of pain sensation and thermoanesthesia may be present and are both noted below the impairment. If a neurologic impairment is suspected, the clinician must first exclude a neoplastic process, infectious process, or fracture, and then consider a disk protrusion. A nondiscal disorder of the thoracic spine could include a neurofibroma; some of the signs to help confirm its presence are that

• the patient reports preferring to sleep sitting up;
• the pain, which slowly increases over a period of months, is felt mainly at night and is uninfluenced by activities;
• the patient reports a band-shaped area of numbness that is related to one dermatome;
• the patient reports the presence of pins and needles sensations in one or both feet or reports any other sign of cord compression.

Brown–Séquard syndrome symptoms may also occur with an idiopathic spinal cord herniation. This syndrome is caused by damage to the lateral funiculus of the spinal cord. The spinal cord frequently is shifted ventrolaterally and sometimes rotated toward the side of tethering, which might cause unilateral damage of the lateral funiculus. For the diagnosis of spinal cord herniation, magnetic resonance imaging (MRI) and computed tomography (CT) myelography are essential. An MRI myelogram can show acute, angular, anterior (ventral) deviation of the spinal cord in the sagittal plane. CT myelograms can detect anterior (ventral) or ventrolateral shifts of the spinal cord and, sometimes, an extradural cyst in the anterior (ventral) epidural space.

Special Tests

Very few special tests exist for this region, and even fewer have undergone diagnostic accuracy studies to determine reliability, sensitivity, and specificity.

Rib Spring Test

The patient is positioned prone, and the clinician stands on one side of the patient. Reaching over the patient, the clinician spreads the length of the thumb and index finger over the right rib in question and applies a posteroanterior force (Fig. 27-18). This is the equivalent of a left rotation of the thoracic spine. The clinician then repeats the posteroanterior force on the rib, except this time, the rotation of the thoracic spine is blocked by the clinician placing the ulnar border of the other hand over a group of left transverse processes. Pain produced with this maneuver implicates the rib, because the thoracic spine is stabilized.

Thoracic Spring Test

The patient is positioned as previously. Spring testing in a posteroanterior direction is applied using the thumbs, with the elbows locked over the spinous processes of the thoracic spine (Fig. 27-19). These spring tests are provocative for pain but may also be used for a gross assessment of mobility.

Reflex Hammer Test

The patient is sitting, and the clinician uses a reflex hammer to tap over each spinous process (Fig. 27-20). If tenderness is encountered, especially in a patient with a history of trauma to the area, a fracture must be ruled out.

Deep Breathing and Flexion

This test can be used for patients who complain of pain with thoracic flexion. The patient is seated with the thoracic spine positioned in neutral. The patient is asked to inhale fully and then to flex the thoracic spine until the pain is felt. At this point, the patient maintains the position of flexion and slowly exhales. If further flexion can be achieved after exhalation, the source of the pain is likely to be the ribs rather than the thoracic spine.133

The Sitting Arm Lift Test.134

The sitting arm lift (SAL) test is based on the principles of the active straight leg raise (see Chap. 29), a validated test of failed load transfer in the pelvic girdle associated with pregnancy-related pelvic girdle pain. The patient is positioned in relaxed sitting with the hand resting on the thighs. The clinician asks the patient to lift one arm (usually the pain-free side is tested first if ipsilaterally symptoms are present), with the arm straight, into elevation and then to lower the arm (Fig. 27-21). Next, the patient is asked to lift the other arm and lower it and the clinician notes whether symptoms are produced, and also observes which arm looks as if it requires more effort to lift, especially from the initiation of movement to the first 70° to 90° of elevation. Then, the patient is asked “does one arm feel heavier to lift on the other, or different to lift than the other?” If one arm is reported to be heavier or required more effort to lift, the test result is positive for loss of neuromuscular control and indicates a load transfer problem. To determine the affected level or levels, the clinician then palpates the osteokinematic motion of each thoracic ring as the patient performs active elevation through flexion with the heavier arm. A positive test result is indicated when a thoracic ring or rings is/are felt to translate along any axis or rotate in any plane, or any component of the ring (vertebra or rib) translates or rotates along any axis or plane.

The Prone Arm Lift Test.134

The prone arm lift (PAL) test is a modification of the SAL test as it is performed in a higher load position (prone). The patient is positioned in prone with both arms overhead in approximately 120 degrees of flexion and fully supported on the bed (the head of the bed needs to be dropped down). The clinician instructs the patient to lift one arm and then lower it (Fig. 27-22). The movement is then repeated on the other side. The arm that tests positive for loss of neuromuscular control is the arm that is heavier to lift. As with the sitting arm lift test, the same techniques can be used to assess the osteokinematic motions. It is particularly important to assess this ability in patients who require this position functionally (e.g., overhead workers).

Interventions for thoracic and rib dysfunctions require a multifaceted and eclectic approach because of the complexity of this area. Once the causes for referral of symptoms have been ruled out, dysfunctions of the thoracic spine and rib cage may be categorized as somatic or biomechanical.

The intervention approaches are for the upper thoracic spine is similar to that of the cervical spine (see Chap. 25), whereas the approach for the lower thoracic spine is similar to that of the lumbar spine (see Chap. 28). The approach to the mid-thoracic region is variable and depends on the cause. This region is prone to both postural and biomechanical dysfunctions. The evidence supporting the use of mobilization and high-velocity thrust techniques in the thoracic spine continues to increase.135–139

The overall goal of treatment should be to optimize load transfer and the sharing of forces throughout the thorax, the spine, and the entire body, which requires restoration of mobility to restrict areas, restoration of muscle control and the capacity to stabilize poorly controlled areas.2

The techniques to increase joint mobility and soft tissue extensibility are described later, under “Therapeutic Techniques” section.

Acute Phase

In the acute phase of rehabilitation for the thoracic spine, the intervention goals are to

• decrease pain, inflammation, and muscle spasm;
• promote healing of tissues;
• increase pain-free range of vertebral and costal motion;
• regain soft tissue extensibility;
• regain neuromuscular control;
• initiate postural education;
• promote correct breathing;
• educate the patient about activities to avoid and positions of comfort;
• allow progression to the functional phase.

Pain relief may be accomplished initially by the use of modalities such as cryotherapy and electrical stimulation, gentle exercises, and occasionally the temporary use of a spinal brace. Thermal modalities—especially ultrasound, with its ability to penetrate deeply—may be used after 48–72 hours. Ultrasound is the most common clinically used deep-heating modality to promote tissue healing.140–142

Electrical stimulation can be used in the thoracic region to

• create a muscle contraction through nerve or muscle stimulation. The purpose of this muscle contraction and stimulation is to create a muscle pump to aid in the healing process. Electrical stimulation of muscles for the correction of scoliosis has not been found to be effective in preventing scoliosis progression143;
• decrease pain through the stimulation of sensory nerves (TENS);
• provide muscle reeducation and facilitation through both motor and sensory stimulation.

Once the pain and inflammation are controlled, the intervention can progress toward the restoration of full strength, range of motion, and normal posture. Range-of-motion exercises are initiated at the earliest opportunity. These are performed during the early stages in the pain-free ranges. Submaximal isometric exercises are then performed throughout the pain-free ranges. These exercises are progressed as the range of motion and strength increase.

Manual techniques during this phase may include myofascial release, grade I and II joint mobilizations, massage, gentle stretching, and muscle energy techniques.

Functional Phase

The duration of this phase can vary tremendously and depends on several factors:

• Severity of the injury
• Healing capacity of the patient
• How the condition was managed during the acute phase
• Level of patient involvement in the rehabilitation program

The goals of this phase are the following:

• To achieve a significant reduction or to complete resolution of the patient's pain.
• To restore full and pain-free vertebral and costal range of motion. During this phase, the patient learns to initiate and execute functional activities without pain and while dynamically stabilizing the spine in an automatic manner.
• Full integration of the entire upper and lower kinetic chains. The exercises prescribed must challenge and enhance muscle performance, while minimizing loading of the thoracic spine and ribs to reduce the risk of injury exacerbation. Interindividual differences in injury status or training goals may allow for a continuum of required muscle stress and acceptable loading of the spine.144
• Complete restoration of respiratory function;
• Restoration of thoracic and upper quadrant strength and neuromuscular control. The stabilization of this region must include postural stabilization retraining of the entire spine, including the stabilization progressions outlined in Chapters 25 and 28, to (1) gain dynamic control of spine forces, (2) eliminate repetitive injury to the motion segments, (3) encourage healing of the injured segment, and (4) possibly alter the degenerative process.145

Practice Pattern 4B: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated with Impaired Posture

Postural Dysfunction

Postural dysfunctions of the thoracic spine are relatively common. Postural pain is not typically reproducible with the typical physical examination, and the diagnosis is based solely on the history of pain following sustained positions or postures. Occasionally, patients with this type of pain may report that their pain is aggravated by stress, or fatigue.146

Maigne's Thoracic Pain of Lower Cervical Origin

Although the pain from this condition may originate in the thoracic spine, Maigne110 believes that the vast majority of these cases originate from the lower three cervical segments. The typical patient is female, with complaints of stiffness and tenderness of the shoulder girdle and thoracic muscle groups, particularly the interscapular muscles. The chief complaint is often described as a unilateral and intense pain, which is increased with sustained positions of sitting, and with the lifting and carrying of heavy weights. The pain generally is decreased with rest, although it can sometimes be worse in the morning upon awakening. There may also be accompanying cervical and low-back pain associated with postural habits or standing or sitting positions.

The physical examination usually reveals tenderness at the level of T5–6 (interscapular point), 1–2 cm lateral of the midline. Mild pressure at this point is sufficient to reproduce the patient's pain.

The intervention for this condition involves a therapeutic trial of cervical mobilization.

Abnormal Pelvic Tilting

Good mobility of the pelvis in all directions is important for the thoracic spine. Two postural deviations are associated with pelvic tilting:

1. Posterior pelvic tilting in the sitting position produces an increase in lumbar and thoracic spine flexion and a forward head posture (FHP). This posture is thought to result in a posterior shifting of the thoracic disk, which in turn places a stress on the posterior longitudinal ligament and the dura mater. This stress can produce both local and nonsegmental referrals of pain. This condition can be treated by having the patient sit on a wedge that tilts the pelvis anteriorly.

2. Anterior pelvic tilting in the standing position causes the trunk to lean backward and results in overstretching of the rectus abdominis and a pulling forward of the shoulders, shortening of the posterior neck muscles, and increased extension of the atlanto-occipital joint.147 This condition can be treated by having the patient perform posterior pelvic tilts while standing, or by standing with one foot in front of the other.

Precordial Catch Syndrome

This is a benign self-limiting condition occurring mainly in adolescents and young adults.148,149 It is characterized by sharp, stabbing pain in the precordial and left parasternal region that does not radiate. This pain usually lasts a few seconds and may occur at rest or with mild-to-moderate exercise.148 When occurring at rest, it is often associated with being seated in a slouched position and may be relieved by stretching into a more upright position.150 It affects males and females equally but is uncommon after the age of 35 years.149 The etiology of this condition is unknown, but it may originate from the pleura.149 After excluding other causes, management consists of explanation, reassurance, postural education, and exercises to correct any muscle imbalances.

Practice Pattern 4D: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated with Ligament or Other Connective Tissue Disorders

Thoracic Disk Pathology

Herniated disks have been found at every level of the thoracic spine, although they are more common in the lower thoracic spine.11,158

At the cervical and lumbar levels, the thoracic spinal nerves emerge from the cord as a large anterior (ventral), and a smaller posterior (dorsal) ramus, which unite to form a short spinal nerve root. There are no plexuses in this area, and the spinal nerves form the intercostal nerves.8 The intraspinal course of the upper thoracic nerve root is almost horizontal (as in the cervical spine). Therefore, the nerve can only be compressed by its corresponding disk. More inferiorly in the spine though, the course of the nerve root becomes more oblique, and the lowest thoracic nerve roots can be compressed by disk impairments of two consecutive levels (T12 root by 11th or 12th disk).8

The major etiological factor in most cases of thoracic disk herniation appears to be degenerative changes in the disk.159 McKenzie123 argues that the derangement syndrome can be divided into posterior and anterior disk derangements because of the distinct clinical presentations. The McKenzie classification system is outlined in Chapter 22. Anterior derangement is rare in the thoracic spine. The following derangement patterns are seen in the thoracic spine123:

• Derangement 1. This type of derangement typically produces central or symmetric pain between T1 and T12. These derangements are rapidly reversible.
• Derangement 2. This type of derangement, which is rare and the result of acute trauma or serious pathology, produces an acute kyphosis.
• Derangement 3. This type of derangement typically produces unilateral or asymmetric pain across the thoracic region, with or without radiation around the chest wall. These derangements are rapidly reversible.

Midline back pain and compressive myelopathy symptoms progressing over months or years are the predominant clinical features of a thoracic disk herniation.160 One study161 found that 70% of patients had signs of spinal cord compression, but that isolated root pain occurred in only 9% of patients. Unusual features of thoracic disk herniation include Lhermitte's symptom precipitated by rotation of the thoracic spine,162 neurogenic claudication with positional dependent weakness,163 and flaccid paraplegia.164

Some thoracic disk herniations are asymptomatic. The incidence of asymptomatic thoracic disk protrusions is approximately 37%, reinforcing the view that clinicians should interpret thoracic MRI findings with caution.11,158

T1 and T2 Levels

Disk herniations at these levels are extremely rare.165 This rarity may be due to the protection afforded by the presence of the first and second ribs. Compression of the nerve at the T1 and at T2 segmental levels may result in numbness, tingling and weakness of the hand, and pain in arm and medial forearm.165 T1 radiculopathy may also be associated with a Horner's syndrome.165 The patient may also have reduced biceps and triceps reflexes.165

T2 and T3 Levels

A disk herniation at these levels is the rarest type.166 Symptoms produced with this herniation include pain referred toward the clavicle, to the scapular spine, and down the inner side of the upper arm.166

T3–8 Levels

Compression of the nerves at these lower levels may result in symptoms that are experienced at the side, or front of the trunk.90 Compression of the dura in the thoracic spine results in unilaterally referred pain, which is extrasegmental. A T6-level compression of the dura can cause pain up to the base of the neck and down to the waist, whereas a dural compression at T12 can refer pain up to T6 and down to the sacrum.90

T9–11 Levels

Lower thoracic disk herniations have been associated with pain radiating to the buttock in some cases, confusing the diagnosis with that of a lumbosacral root compression.167 How a herniated disk at a low thoracic level could appear to be a lumbosacral radiculopathy may be best explained by the anatomic arrangement of the spinal cord and vertebral bodies. In adults, the conus medullaris ends between the 12th thoracic and third lumbar vertebrae, and the lumbar enlargement of the spinal cord is usually located at the lower thoracic level. Therefore, a lower thoracic disk herniation could compress the lumbosacral spinal nerves after their exit from the lumbar enlargement of the spinal cord and thus produce symptoms of compressive lumbosacral radiculopathy; thus, a herniation into an already tight canal may produce bilateral symptoms and sphincter disturbance, as in patients with a conus medullaris impairment.168

A retrospective study by Brown and colleagues169 found that 77% of the 40 patients with symptomatic thoracic disk herniations, who were treated nonsurgically, were able to return to their previous level of activity.

Thoracic disk herniations requiring surgical management are uncommon and account for less than 2% of all operations performed on herniated IVDs.170

Electrodiagnosis of Thoracic Disk Lesions

Electrodiagnostic studies are important in identifying physiologic abnormalities of the nerve root in the cervical, thoracic, and lumbar spine, and they have been shown to be a useful diagnostic test in the diagnosis of radiculopathy,171 correlating well with findings on myelography and surgery.172,173

There are two parts to the electromyogram: nerve conduction studies and needle electrode examination. The nerve conduction studies are performed by placing surface electrodes over a muscle belly or sensory area and stimulating the nerve, supplying either the muscle or the sensory area from fixed points along the nerve. From this, the amplitude, distal latency, and conduction velocity can be measured. The amplitude reflects the number of intact axons, whereas the distal latency and conduction velocity are more of a reflection of the degree of myelination.174–176

The timing of the examination is important, as positive sharp waves and fibrillation potentials will first occur 18–21 days after the onset of a radiculopathy.175,177 It is, therefore, best to delay this study until 3 weeks after the injury, so that it can be as precise a study as possible. The primary use of electromyography is to diagnose nerve root impairment when the diagnosis is uncertain or to distinguish a radiculopathy from other impairments that are unclear on physical examination.175 Electrodiagnostic abnormalities can persist after clinical recovery for months to years and in some may persist indefinitely.178,179

Traction: Mechanical or Manual for Thoracic Disk Lesions

Manual or mechanical traction has long been a preferred intervention throughout the spine with the intent of improving range of motion, and to treat both zygapophyseal joint impairments as well as disk herniation.180–185 The efficacy of traction has not been scientifically proved in a randomized controlled trial, but it is commonly used and thought to be of benefit in reducing radicular pain.186

For traction to be effective, the imparted force must be sufficient to overcome soft tissue resistance prior to the relaxation of the involved musculature.

Traction can be applied continuously, or intermittently, and with the patient positioned in sitting or lying.187 Intermittent traction produces twice as much separation as sustained.188 The duration of traction recommended varies from 2 minutes to 24 hours.189

Performed manually, traction can be very time consuming and, in the lumbar and thoracic spines, requires a good deal of strength—approximately 12 times a patient's body weight is needed to develop significant distraction of the vertebral bodies. However, a greater degree of specificity can be obtained using manual traction, especially if it is performed using spinal locking techniques to localize the distraction to a specific level. Pain relief, or a centralization of symptoms, with manual traction may also be an indication for the use of mechanical traction.

Vertebral axial decompression, a newer method to cause distraction, probably represents a higher-tech version of traction, although there is no evidence in the current peer-reviewed literature to support this type of intervention.

Outcome studies of traction have demonstrated varying results.180,185 From clinical experience, it would appear that traction yields better results if at least one of the spinal motions is full and pain free. However, a one-session trial of short duration is worthwhile, even if all of the motions are restricted.

Spinal traction is contraindicated in the following conditions:

• acute lumbago;
• instability;
• respiratory or cardiac insufficiency;
• respiratory irritation;
• painful reactions;
• a large extrusion;
• medial disk herniation;
• altered mental state; this includes the inability of the patient to relax.

Electrotherapeutic and Physical Modalities of Thoracic Disk Lesions

Modalities such as electrical stimulation also have been found helpful in uncontrolled studies.190 They appear to be helpful in reducing the associated muscle pain and spasm but should be limited to the initial pain-control phase of the intervention.

Once there is control of pain and inflammation, the patient's intervention should be progressed to restore full range of motion and flexibility of the spine, trunk, and extremity muscles.

Zygapophyseal Joint Dysfunction

Apart from the upper and lower segments of this region, little is known about the extent or patterns of thoracic zygapophyseal joint degeneration. However, these joints have been found to be potential sources of local and referred pain.191

The pathomechanics describing mechanical dysfunction in this region are largely based on expert opinion and the principles of anatomy and biomechanics. Given the controversy surrounding the nature of coupled motions in the thoracic spine, and the number of structures involved in executing motion at these levels, the clinician is advised to diagnose dysfunction in this region based on restrictions of motion, rather than on specific structures.

Restriction of motion can have many causes in this region, including zygapophyseal joint hypomobility, soft tissue contracture, and costovertebral–costotransverse joint hypomobility. Differentiation among these structures, to find the specific cause of dysfunction, requires a great deal of expertise.

For the sake of simplicity, and because the spinous and transverse processes are more easily palpated in this region, the osteopathic approach of diagnosing a positional dysfunction using position testing is recommended.

As elsewhere in the spine, dysfunctions can be either symmetric or asymmetric. Symmetric impairments are more common in the thoracic region than in the lumbar, particularly in the upper and cervicothoracic spine as a result of fixed postural impairments. These, of course, will not be apparent on position testing and must be sought after when the position tests are negative. If no asymmetry is found on position testing, then the segment of interest should be separately passively flexed, extended, and rotated in all directions.

To determine which lesion is present, layer palpation is used. The position of the superior vertebra and the posteroanterior relationship of the transverse processes to the coronal body plane is noted and compared with the level above and below, in thoracic flexion and then extension (see “Position Testing: Spinal” section earlier).

Rib Dysfunction

The costovertebral joint may be involved in inflammatory or degenerative joint disease. Complaints of symptoms in these joints are common in conditions such as ankylosing spondylitis as a result of synovitis. The clinical features of severe arthropathy of the costovertebral joint include pain with deep breathing, trunk rotation, sneezing, or coughing. CT scans are helpful in confirming the diagnosis. Inflammation of the costovertebral joint commonly causes localized pain about 3–4 cm from the midline, where the rib articulates with the transverse process and the vertebral body.81

According to the osteopaths, rib dysfunctions are described as structural, torsional, or respiratory.117,192,193

• Structural. Structural rib dysfunctions are true joint subluxations that occur secondary to trauma. These dysfunctions are extremely painful and significantly reduce motion of the ribs during inspiration and expiration. The most important landmarks for structural rib dysfunctions are the rib angle and the anterior rib. Ribs can sublux anteriorly or posteriorly (see Table 27-4). The first rib can sublux superiorly.
• Torsional. As their name suggests, these rib dysfunctions are twisting injuries, in which the rib is held in a position of internal or external rotation. These dysfunctions affect the thoracic spine motions as well as the motions of respiration (see Table 27-4).
• Respiratory. Respiratory rib dysfunctions usually are related to poor posture and result in a restriction of either inspiration or expiration.

The first rib can sublux anteriorly, posteriorly, or, more commonly, superiorly. If the motion is perceived as abnormal, passive movement testing should be performed. The arthrokinematic is tested with the patient seated and the clinician standing behind. Using the medial aspect of the MCP joint of the index finger, the clinician applies an anterior–inferior–medial glide of the rib to assess the inspiration glide, while a posterior–superior–lateral glide is applied to assess the expiration glide. The end-feel is assessed. If it is abrupt and hard (pathomechanical) in both glide directions as compared with the same rib on the other side, then the problem is a subluxation. If it is stiff (hard capsular) in both directions as compared with the same rib on the other side, then a pericapsular restriction is present. If both glides are normal, then the problem is likely to be myofascial.

• Unilateral restriction of anterior rotation of the first rib. This dysfunction is seen when the scalene muscles are hypertonic or adaptively shortened and hold the anterior aspect of the first rib superiorly or when the superior glide of the first rib is restricted at the costotransverse joint. This dysfunction will restrict unilateral elevation of the arm (both arms may be involved). If the dysfunction is intra-articular, rotation and side bending of the head/neck will be limited to the side of the restricted rib (this motion requires a superior glide of the rib at the costotransverse joint). Full expiration will also reveal asymmetry of rib motion. If the restriction is intra-articular, the superior glide of the first rib at the costotransverse joint will be restricted. The presence or absence of pain depends upon the stage of the pathology (substrate, fibroblastic, and maturation) and the irritability of the surrounding tissue. The grade of the mobilization technique is directed by these factors.
• Unilateral restriction of posterior rotation of the first rib. This dysfunction, also known as an expiratory or anterior sagittal lesion, is seen when the posterior aspect of the first rib is held superiorly or when the inferior glide of the first rib is restricted at the costotransverse joint. This dysfunction will restrict unilateral elevation of the arm on either side, rotation and side bending of the head/neck to the opposite side of the restricted rib, and full inspiration. If the restriction is intra-articular, the inferior glide of the first rib at the costotransverse joint will be restricted. The presence or absence of pain depends on the stage of the pathology (substrate, fibroblastic, and maturation) and the irritability of the surrounding tissue. The grade of the mobilization technique is directed by these factors.

The intervention for costovertebral dysfunctions involves mobilization and manipulation techniques or local anesthetic injections, or both.

Practice Pattern 4E: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated with Localized Inflammation

Tietze Syndrome

Tietze syndrome is a local inflammation of the costosternal cartilage, which most commonly affects the second and third costochondral junctions.27,153 Tietze syndrome may also affect any of the cartilaginous articulations of the chest wall, including the sternoclavicular joints.194

The clinical findings for this condition include a history of a gradual or sudden onset of pain in the involved region, which is increased with deep inspiration, coughing, or sneezing. Upon physical examination, there is often a localized swelling of the costosternal cartilage.

This is a self-limiting condition, which can last from weeks to years. The intervention can involve local injections of corticosteroid and specific joint mobilizations to the costovertebral articulations.

Muscle Strains

Muscle strains, which are common in this region, are characterized by localized pain and tenderness, which is exacerbated with isometric testing or passive stretching of the muscle. Rather than attempt to isolate muscles in this region, the clinician can determine the directions that alleviate the symptoms and those that do not. A gradual strengthening and gentle passive stretching program into the painless directions is initially performed, before progressing as tolerated into the painful directions.

Intercostal Muscles

Injuries to intercostal muscles are mainly caused by direct trauma or after unaccustomed or excessive muscular activity (e.g., lifting a heavy object or persistent coughing).195 On occasion, the onset of pain or symptoms may be of gradual onset with no obvious inciting event.196 Intercostal muscle injuries are more likely in activities in which upper body use is extreme, such as regular use of a pickaxe.196

The classic presentation is pain between the ribs that is worse on movement, deep inspiration, or coughing, and tender to palpation.

The intervention for intercostals muscle strains includes anti-inflammatory medications, the avoidance of exacerbating activities, and the treatment of any underlying pathology where appropriate.

Contusions

The severity of soft tissue injury to the chest wall is dependent on the mechanism of injury and the degree of protection between the traumatic force and the chest wall.55 Chest injury is commonly produced by the restraining influence of the diagonal component of a seat belt. Seat belt injuries occur predominantly on the side of the belt and hence occur on different sides in drivers and passengers.55 These take the form of abrasions, ecchymoses, and friction burns, producing an imprint of the belt.55

Trauma to the female breast can be produced by a combination of compression and shearing stress produced by a seat belt, and subcutaneous rupture of breast tissue can occur.197 The presence of a persistent breast mass after trauma must always be taken seriously, as trauma may draw attention to an unsuspected carcinoma.55

Chest trauma can result in disruption of a subcutaneously placed pacemaker generator or leads, long-term indwelling central venous catheter, or subcutaneous portions of arterial bypass grafts.55

Severe skeletal trauma to the chest wall can be associated with large chest wall hematomas or collections of air within the chest wall, which can communicate with the intrathoracic space.55

The conservative intervention for thoracic cage contusions depends on the severity of the injury and the tissues involved. Typically, the initial intervention for soft tissue injury is cryotherapy with rest. Gentle pain-free active range-of-motion exercises are introduced as tolerated. Once the acute stage is over, thermal modalities are used and the range of motion exercises progressed to strengthening exercises in all planes.

Practice Pattern 4G: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated with Fractures

Thoracic Vertebral Fractures

Fractures of the thoracic spine account for 25–30% of all spine fractures.198 These fractures are most often a result of hyperflexion or axial loading injuries199 and less commonly attributable to rotational stresses, side bending, horizontal shear, and hyperextension. The most common fractures seen in the thoracic spine are anterior wedge compression fractures and burst fractures200 (see Chap. 5). Most thoracic spine fractures occur between the ninth and 11th vertebral bodies. Multiple fractures are found in 10% of all patients with a spine fracture, and, therefore, evaluation of the entire spine is necessary, because up to 80% of these additional fractures are noncontiguous.201 Only 12% of patients with fracture–dislocations of the thoracic spine are neurologically intact, and 62% of patients with thoracic spine fracture–dislocations have complete neurologic deficits.55

Rib Fractures

Fractured ribs can lacerate the pleura, lung, or abdominal organs. Fractures to upper ribs, clavicle, and upper sternum can signal brachial plexus or vascular injury. Isolated fractures of the ribs, clavicle, or scapula seldom represent significant injuries in and of themselves, but they do reflect the magnitude of force imparted, particularly in older patients with noncompliant chest walls.202 Fractured rib ends can lacerate the pleura or lung, resulting in hemothorax or pneumothorax.55 There is a much greater incidence of rib fractures in older patients, whose ribs are relatively inelastic, compared with the incidence of rib fractures in children, whose ribs are more pliable and resilient.55 For this reason, a posttraumatic pneumothorax in older patients is almost always associated with one or more rib fractures, whereas children can sustain a pneumothorax or major internal thoracic injury after trauma without an associated rib fracture.

Fractures of the first three ribs, in particular, indicate significant energy transfer, because they are well protected by the shoulder girdles and associated musculature.55 Fractures to the upper ribs, clavicle, and upper sternum are accompanied by brachial plexus or vascular injury in 3–15% of patients.203 Fractures of the 10th, 11th, or 12th ribs are associated with injury to the liver, kidneys, or spleen and should prompt confirmation of organ injury with CT.55 Double fractures of three or more adjacent ribs or contiguous combined rib and sternal or costochondral fractures, or single fractures of four or more contiguous ribs, can produce a focal area of chest wall instability. Paradoxical movement of a “flail” segment during the respiratory cycle can impair respiratory mechanics, promote atelectasis, and impair pulmonary drainage.

The common findings for a rib fracture are described in Chapter 5. A key factor in the intervention of rib fractures is believed to be adequate pain control to allow early aggressive respiratory care and, hence, prevent the development of pulmonary complications.

Early intervention includes assistance with coughing, intracostal nerve blocks, and muscle relaxants. Adhesive strapping or taping should be avoided because it can inhibit deep inspiration and may contribute to atelectasis.204 Simple rib fractures become stable in 1–2 weeks, with firm healing by callus in approximately 6 weeks.204

Scheuermann's Disease

Scheuermann's disease, which is found in approximately 10% of the population and in males and females equally, is typically seen in pubescent athletes.21

The disease involves a defect to the ring apophysis of the vertebral body and anterior wedging of the affected vertebrae, as a result of a flexion overload of the anterior vertebral body.205 The end plate can crack, thus making it possible for disk material to bulge into the vertebral body (Schmorl's node). According to McKenzie,123 the extension dysfunction develops in patients with Scheuermann's disease as a result of adaptive shortening from poor postural habits, or from derangement or trauma and the healing process.

Clinical findings include evidence of a thoracic kyphosis and pain with thoracic extension and rotation.

The intervention depends on the severity but typically involves postural education, a modification of the aggravating activity, exercise (seated rotation and extension in lying exercises), or bracing. The exercise program involves the stretching of the pectoralis major and minor muscles, and muscle-strengthening exercises for the thoracic spine extensors and the scapular adductors.38

Scapular Fractures

Fractures of the scapula are relatively rare due to the thick muscles lying both superficial and deep to the scapula and the energy-absorbing ability of the scapula to move on the chest wall.206 Because of the large amount of force that is required to fracture a scapula, these fractures are often associated with other major injuries. For example, the incidence of pneumothorax in patients with fracture of a scapula is over 50%.207 Associated injuries that are directly related to the fractured scapula include injuries of the suprascapular nerve, axillary nerve, axillary artery, and subclavian artery.55 The body of the scapula is the most frequent site of fracture followed by the neck and glenoid.208 The spine, coracoid, and acromion are less frequently fractured.208 Scapular fractures may not be recognized on the initial chest radiograph as they are frequently radiographically obscure and are commonly associated with multiple other regional injuries, such as clavicular and rib fractures, subcutaneous air, pneumothorax, and pulmonary contusion.55

Sternal Fractures

The tremendous force necessary to cause a fracture of the sternum has led to the belief that the presence of a sternal fracture is a harbinger of severe associated injuries. The association of seat belt wearing with sternal fractures is well known.209 A proportional increase in incidence of 100% in drivers and 150% in front-seat passengers has been noted since the enactment of seat belt legislation.210 Sternal fractures, as such, do not generally cause problems either in healing or by direct damage to adjacent structures. Dislocation of the sternoclavicular joint, however, with posterior displacement of the inner end of the clavicle may cause compression of the trachea and the adjacent great vessels, with significant clinical consequences.211

Integration of Practice Patterns 4B and 4F: Impaired Joint Mobility, Motor Function, Muscle Performance, Range of Motion Secondary to Impaired Posture, Systemic Dysfunction (Referred Pain Syndromes), Spinal Disorders, and Myofascial Pain Dysfunction

Referred Pain

Referred pain to this area is extremely common. Referred pain is characterized by a poorly localized pain that is nontender to palpation and does not change with movements or alterations of posture (see Table 27-6).

T4 Syndrome

The name of this syndrome is a bit of a misnomer, because the syndrome can additionally affect any of the T2–7 levels, although it always includes the T4 segment. The T4 syndrome has an unknown etiology, although it is believed to result from a sympathetic reaction to a hypomobile segment, because the symptoms appear to resolve in response to manual therapy techniques to the thoracic segments.212–214 In the thorax, the sympathetic trunks lie on or just lateral to the costovertebral joints. These trunks may undergo mechanical deformation with abnormal posture (forward head, accentuated thoracic kyphosis, and protracted shoulder girdle), trauma, or pulling and reaching activities, producing pain and sympathetic epiphenomena.215

Neurovascular symptoms are not a feature of this syndrome, though a differential diagnosis should consider such conditions.212 The upper extremity symptoms are glovelike in distribution and are not segmentally related.213 Nocturnal symptoms are common, usually occurring in the side lying or supine position.213 More women are affected by this condition than men, in a ratio of more than 3:1.216

Clinical findings include local tenderness of bony points, positive slump test, positive upper limb tension tests, depression or prominence of one or more spinous processes, and local thickening and stiffness of one segment,216 although gross cervical and thoracic motions are usually normal.212

The differential diagnosis includes carpal tunnel syndrome, thoracic outlet syndrome (see Chap. 25), cervical disk disease, vascular disease, and neurologic disease.212

The intervention for this condition involves mobilization and manipulation of the involved segment, followed by an exercise progression emphasizing upper thoracic flexibility and muscle strength. Butler217 recommends using both upper limb tension tests and also the slump test, with combinations of thoracic rotation and side bending.

Notalgia Paresthetica

The name of this condition comes from the Greek root meaning “pain in the back.”218 Clinically, this condition consists of pruritus and localized dysesthesia and hyperesthesia in the distribution of one of the cutaneous posterior (dorsal) rami of the upper thoracic area.

The recommended intervention for this condition is an injection of corticosteroid.

The selection of a manual technique is dependent on a number of factors, including the acuteness of the condition and the restriction to the movement that is encountered. Oftentimes, the same technique that was used to examine the segment can be used for the intervention, the difference being the intent of the clinician and the goal of the intervention. For example, if stretching of the mechanical barrier rather than pain relief is the immediate objective of the intervention, a mobilization technique is carried out at the end of the available range.

To achieve this, the antagonist muscle must be relaxed, and this is most easily accomplished using a hold–relax technique. After this has been gained (and sometimes before and after), there is some minor pain to be dealt with, using grade IV oscillations, after which the joint capsule can be stretched, using either grade IV++ or prolonged stretch techniques. The prolonged stretch or the strong oscillations are continued for as long as the clinician can maintain good control. At the point where control is about to be lost, several isometric contractions to the agonists and the antagonists are demanded of the patient's muscles in the new range, to give the central nervous system information about the newly acquired range. To complete the reeducation, concentric and eccentric retraining is carried out throughout the whole range of the joint. Active exercises are continued at home and at work on a regular and frequent basis, to reinforce the reeducation.

Techniques to Increase Joint Mobility

Joint Mobilizations and High-Velocity Thrust Techniques

Mobilization and high-velocity thrust techniques have traditionally been used routinely in this region to29,86,219,220:

• restore thoracic mobility;
• reduce stresses through both the fixation and the leverage components of the spine;
• reduce stresses through the hypermobile segments;
• reduce the overall force needed by the clinician, thus giving greater control.

A number of studies have demonstrated clinical success with high-velocity thrust techniques to the thoracic spine.135,139,224,225 However, it must be remembered that the isolation of a particular segment in the thoracic spine is extremely difficult, if not impossible because of the number of articulations that exist at each segmental level. In addition, there are a number of concerns that the clinician must be aware of prior to considering using high-velocity thrust techniques in this region. These include the following:

• A number of studies have demonstrated that the meninges may be vulnerable to thoracic manipulative thrust techniques.226,227
• The narrow dimensions of the mid-thoracic spinal canal.
• The poor blood supply to this region as compared to other areas of the spine.53
• The potential fragility of the bones in this area due to such conditions as osteoporosis, and rheumatoid arthritis.

It is, therefore, recommended that the clinician performs the slump test (see Chap. 11) and a premanipulative hold (see Chap. 10) prior to any technique.

Long Sit Superior Distraction (T5–6)

The patient is positioned on the treatment table in the long sit position, with the buttocks on the edge of the back of the table and the hands on the back of the neck, fingers interlocked. The clinician stands behind the patient and places a small towel roll at the T6 level. The towel roll is held in place by the clinician's chest (made easier if the clinician turns slightly so that the side of the chest is used). The clinician threads his or her arms under the patient's armpits and places the heel of the palms under the patient's forearms. The patient is asked to flex the neck. A stride stance (one foot in front of the other) is adopted by the clinician (Fig. 27-23), and, while keeping the elbows close together, the clinician gently rocks the patient backward and forward. After two or three rocks, the traction force is applied, as the clinician shifts his or her body weight from the forward leg to the back, while lifting the patient and pushing the patient's forearms toward the ceiling.

Exercises to Increase Soft Tissue Extensibility

Shoulder Sweep. This exercise is used to mobilize the chest wall and to integrate upper extremity function with thoracic spine and rib cage motion.61

The patient is positioned supine on the floor or on a mat table, with the hips and knees flexed to about 90 degrees (Fig. 27-24). The patient is asked to reach sideways and place the back of the hand as far out to the side as is comfortable. While maintaining contact with the floor, the patient moves the hand above the head and to the other side of the body, making a large circle around his or her body (see Fig. 27-24). Manual assistance applied to the scapula or rib cage can be used as can deep breathing, in order to move into the restricted ranges.

Thoracic Spine Flexion

The patient kneels in front of a Swiss ball. The patient positions themselves over the Swissball so that weight is applied through the feet and the forearms (Fig. 27-25). While applying some body weight through the forearms, the patient arches the thoracic spine as far as is comfortable. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated 8–10 times.

Thoracic Spine Extension

It is advised that the clinician monitor this exercise in case the patient loses his or her balance. The patient sits on a Swiss ball, with the feet on the ground. Once the patient has good sitting balance, he or she attempts to lie supine on the ball and then places the hands on the ball (Fig. 27-26). The patient is then instructed to move the top of the head toward the floor, in an attempt to fully extend the thoracic spine. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated eight to 10 times. This exercise can be made more challenging by moving the hands from beside the body, out to the sides (Fig. 27-27) while maintaining the balance.

If the patient is unable to maintain his or her balance on the Swiss ball, a foam roll may be used. The foam roll also allows the clinician to focus the extension exercise on a specific segment.

Thoracic Spine Rotation

The following Swiss ball exercises to improve thoracic rotation range of motion and strength are recommended for the athletic population, only. The patient kneels with his or her back facing the Swiss ball. Using one leg at a time, the patient reaches back with the foot and places it on top of the Swiss ball. Once both feet are on the ball, the legs are straightened and the weight of the body is primarily borne through the arms. Using the dorsum of the feet and the anterior legs, the patient induces a rotation to the thoracic region by twisting at the waist (Fig. 27-28), while maintaining balance through the arms. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated 8–10 times. By alternatively moving the legs into hip flexion and extension, rotation of the thoracic spine can be achieved, while maintaining balance with the arms (see Fig. 27-28).

For the nonathletic population, thoracic rotation exercises can be performed using a firmer base of support. The patient kneels in front of a wobble board and places both hands on the board. Once good balance is achieved, the patient is asked to raise one arm out to the side as high as is comfortable, while keeping both knees on the floor. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated eight to 10 times.

Thoracic rotation exercises can also be performed in the supine position. The patient lies supine with both knees bent and feet placed on the floor. The arms are abducted to approximately 90 degrees (Fig. 27-29). Keeping the trunk against the floor, the patient lowers the thighs to one side and then the other (see Fig. 27-29), as far as is comfortable. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated eight to 10 times.

Thoracic Spine Side Bending

The patient kneels to the side of a Swiss ball. The patient is asked to lean sideways over the ball and, with the arm closest to the ball, to attempt to touch the floor on the other side of the ball (Fig. 27-30) without losing balance. This position is held for 8–10 seconds, after which the patient relaxes. The exercise is repeated eight to 10 times.

Rib Techniques for the Mid-Lower Thoracic Spine

Myofascial Stretch into Extension

The patient is positioned supine, and the clinician stands at the head of the bed. The patient elevates both arms over the head and reaches around the back of the clinician's thighs. By having the patient hold a towel in this position, the clinician can place both of his or her hands under the patient's rib cage and pull the rib cage in an anterior and cranial direction, thereby encouraging thoracic extension (Fig. 27-31). A belt wrapped around the patient at the correct level can make this technique more specific.

History

A 25-year-old man presented at the clinic complaining of pain in his right anterior chest. About 1 month previously, the patient had experienced a sudden and sharp pain in his right posterior chest at the midscapular level during a tug of war game at his company's picnic. The posterior chest pain subsided very quickly and did not bother him for the rest of the game. However, the next morning, pain was felt in the anterior aspect of the chest. This anterior chest pain eased off over the next few days with rest, but recurred as soon as the patient returned to weight lifting.87

Questions

• 1. Given the mechanism of injury, what structure(s) could be at fault?

• 2. Should the report of anterior chest pain concern the clinician in this case?

• 3. What is your working hypothesis at this stage? List the various diagnoses that could present with anterior chest pain, and the tests you would use to rule out each one.

• 4. Why do you think the pain shift from posterior thoracic to anterior thoracic?

• 5. Does this presentation/history warrant a scan? Why or why not?

History

A 30-year-old housewife presents at the clinic with a 3-day history of constant central and bilateral upper thoracic pain that is deep and dull and can be felt in the front of the chest when the pain is aggravated. The pain is reported to be worse with flexion motions but is improved with lying on a hard surface. Further questioning revealed that the patient had a history of minor back pain but was otherwise in good health and had no report of bowel or bladder impairment.

Questions

• 1. What structure(s) could be at fault with central and bilateral upper thoracic pain as the major complaint?

• 2. Should the report of anterior chest pain concern the clinician in this case?

• 3. Why was the statement about “no reports of bowel or bladder impairment” pertinent?

• 4. What is your working hypothesis at this stage? List the various diagnoses that could manifest with central and bilateral upper thoracic pain and the tests you would use to rule out each one.

• 5. Does this presentation/history warrant a scanning examination? Why or why not?

History

A 42-year-old right-handed female was referred by her primary-care physician with a diagnosis of neck sprain. 228 The patient reported a 10-year history of intermittent neck pain (right greater than left), which had worsened over the past 6 months. More recently, the patient reported developing right shoulder (right upper trapezius) and arm pain, as well as infrequent (about twice a week) paresthesia in the right arm and hand involving the fourth and fifth digits. The patient described the pain as a sharp stabbing pain at the right side of the neck and a dull aching pain in the right upper trapezius region. She indicated that the neck pain was independent of the upper trapezius pain. At the time of the evaluation, the neck and upper trapezius pain were a 3/10 and 4/10, respectively. The symptoms improved when she positioned herself supine or left side lying with a pillow under the head. The upper trapezius pain was reduced when she side bent the head toward the side of pain and worsened as the day progressed, especially when she was at work and performing elevated arm activities. She reported that the paresthesias of the ulnar aspect of a right forearm, as well as digits 4 and 5, appeared more often during the afternoon and occasionally at night. When inquiring about the irritability of the condition, the patient reported that between a few hours and 1 day were required for the pain to decrease after it was provoked. The patient worked as a faculty member at a local college, which involved spending prolonged periods of time on the computer and extensive reading. The patient's past medical history was negative for dizziness, diplopia, unexpected weight change, drop attacks, dysarthria, dysphagia, tinnitus, and night pain unrelated to position.

Questions

• 1. List the structure(s) that could be at fault with these complaints.

• 2. Does this sound like a neuromusculoskeletal condition?

• 3. Are there any other questions you would ask this patient?

• 4. What is your working hypothesis at this stage? List the various diagnoses that could manifest with central and bilateral upper thoracic pain and the tests you would use to rule out each one.

• 5. Does this presentation/history warrant a scanning examination? Why or why not?

History

A 21-year-old woman presented with a 1-week history of left-sided interscapular pain that started at work. The patient worked as a computer operator. The pain was reported to be aggravated by lying prone, deep breathing in, and standing or sitting erect. Further questioning revealed that the patient had a history of this pain over the past few months but that it had not been as intense as it was currently. The patient was otherwise in good health and had no reports of bowel or bladder impairment.

Questions

• 1. List the structures that can produce interscapular pain.

• 2. Given the fact that this patient works at a computer, what could be the cause of her pain?

• 3. What is your working hypothesis at this stage? List the various diagnoses that could manifest with interscapular pain and the tests you would use to rule out each one.

• 4. Does this presentation/history warrant a scan? Why or why not?

• 1. In the thoracic region, in which plane are the zygapophyseal (facet) joints oriented?

• 2. Which of the ribs are considered atypical ribs, and why?

• 3. What is the joint where the rib and the vertebra meet called?

• 4. Which structures modify and restrict rotation in the thoracic region?

• 5. Which ribs demonstrate bucket handle movement and which display pump handle motions?

Answers