Chapter 29. The Sacroiliac Joint

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

1. Describe the anatomy of the bones, the ligaments, the muscles, and the blood and nerve supply that comprises the sacroiliac (SI) region.

2. Describe the biomechanics of the sacroiliac joint (SIJ), including coupled movements, normal and abnormal joint barriers, kinesiology, and reactions to various stresses.

3. Perform a detailed objective examination of the SIJ, including palpation of the articular and the soft tissue structures, specific passive mobility tests, passive articular mobility tests, and stability tests.

4. Evaluate the total examination data to establish the diagnosis.

5. Describe the intervention strategies based on clinical findings and established goals.

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

7. Apply active and passive mobilization techniques, and combined movements to the SIJ, in any position using the correct grade, direction, and duration.

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

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

10. Plan an effective home program and instruct the patient in this program.

The SIJ serves as the supporting base of the spine and as the point of intersection between the spinal and the lower extremity joints. The SIJ is the least understood and, therefore, one of the most controversial and interesting areas of the spine. Determining a diagnosis in this region is complicated by the biomechanics of the SIJ and its relationships with the surrounding joints including the hip, pubic symphysis, and lumbar spine.

Grieve1 has proposed that the SIJ, together with the other areas of the spine that serve as transitional areas, is of prime importance in understanding vertebral joint problems. This level of importance is perhaps surprising, because isolated pelvic impairments are rare. However, findings for SIJ dysfunction appear to be common, and the literature is replete with intervention techniques aimed at correcting pelvic dysfunctions.2–12 This may be explained by the fact that, in addition to producing pain on its own, the pelvic joints often can refer pain.13

The level of interest surrounding this joint dates back to the Middle Ages, a time when the burning of witches was commonplace.14 It was noticed after these burnings that three of the bones were not destroyed: a large triangular bone and two very small bones. It can only be assumed that some degree of significance was given to the large triangular bone as it was deemed a sacred bone, and was thus called the sacrum. It is unclear what significance was given to the two smaller bones, the sesamoid bones of the great toe.

Despite these illustrious beginnings for the sacrum, it was not until approximately 100 years ago that significant attention was applied to the study of pelvic anatomy and function, and its relationship to low back and pelvic pain. At the start of the 20th century, SIJ strain was thought to be the most common cause of sciatica.15 Then, in 1934, Mixter and Barr16 reported that sciatica could be caused by a prolapsed intervertebral disk, and the interest in the SIJ as a source of sciatica dwindled. Since then, there have been periods when the joint has been blamed for almost all low back and leg pain, and times when it has only been considered a problem during pregnancy. It is now generally accepted that approximately 13% (95% CI: 9–26%) of patients with persistent low back pain have the origin of pain confirmed as the SIJ.17

Anatomically, the SIJ is a large diarthrodial joint that connects the spine with the pelvis (Fig. 29-1) and which serves as a central base through which forces are transmitted both directly and indirectly. Three bones comprise the SIJ: two innominates and the sacrum.

Innominates

The ilium, ischium, and pubic bone fuse at the acetabulum to form each innominate (Fig. 29-1). The ilium of each of the two innominates articulate with the sacrum, forming the SIJ, and the pubic bone of each of the innominates articulate with each other at the symphysis pubis.18

Sacrum

The sacrum (Fig. 29-1), a strong and triangular bone located between the two innominates, provides stability to this area and transmits the weight of the body from the mobile vertebral column to the pelvic region. The sacrum base is above and anterior, and its apex below and posterior (Fig. 29-1). Five centra fuse to form the central part of the sacrum, which contains remnants of the intervertebral disks enclosed by bone. The sacrum has four pairs of pelvic sacral foramina for transmission of the anterior (ventral) primary rami of the sacral nerves and four pairs of posterior (dorsal) sacral foramina for transmission of the posterior (dorsal) primary rami.

The transverse processes of the first sacral vertebra fuse with the costal elements to form the ala and the lateral crests (see Fig. 29-1). The ala of the sacrum forms the superolateral portions of the base. The superior articular processes of the sacrum (Fig. 29-1), which are concave and oriented posteromedially, extend upward from the base to articulate with the inferior articular processes of the fifth lumbar vertebra.

On the posterior (dorsal) surface of the sacrum is a midline ridge of bone called the median sacral crest, which represents the fusion of the sacral spinous processes of S1 to S4. Projecting posteriorly from this crest are four spinous tubercles. The fused laminae of S1 to S5, which are located lateral to the median sacral crest, form the intermediate sacral crest.

The sacral hiatus exhibits bilateral downward projections that are called the sacral cornua. These projections represent the inferior articular processes of the fifth sacral vertebra and are connected to the coccyx via the intercornual ligaments. On the inferolateral borders of the sacrum, approximately 2 cm to either side of the sacral hiatus, are the inferior lateral angles (ILAs). The triangular sacral canal houses the cauda equina. In addition to the more commonly considered bones and joints are those of the coccygeal spine.

Sacroiliac Joint

The articulating surfaces of this joint differ, with the iliac joint surfaces formed from fibrocartilage and the sacral surfaces formed from hyaline cartilage.19 The hyaline cartilage is three to five times thicker than the fibrocartilage20 and so between the sacral and iliac auricular surfaces, the SIJ is deemed a synovial articulation or diarthrosis.21

The inverted, L-shaped, auricular articular surface of the sacrum (Fig. 29-1) is surrounded entirely by the costal elements of the first three sacral segments. The short (superior) arm of this L-shape lies in a craniocaudal plane, within the first sacral segment, and corresponds to the depth of the sacrum (see Fig. 29-1). It is widest superiorly and anteriorly. The long (inferior) arm of the L-shape lies in an A-P plane, within the second and third sacral segments, and represents the length of the sacrum from top to bottom. It is widest inferiorly and posteriorly. There are large irregularities on each articular surface22 that are roughly, though not exactly, reciprocal, with the sacral contours being generally deeper.23,24 In addition to the larger irregularities, there are smaller horizontal crests and hollows that run anteroposteriorly. The sacral articular surface is wedge shaped in its upper portion, formed by the first sacral segment and half of the second. Below this, the joint surfaces run nearly vertically and then diverge somewhat, making a flare which tends to prevent the sacrum from sliding upward between ilia.24

Variations in the SIJ morphology are so common that they have been classified as type A, being less vertical than type B, and type C as an asymmetric mixture of types A and B.5 Each of these variants can alter the function of the pelvis and its influence on the lumbar lordosis.25

The articulating surfaces of the joint respond differently to the aging process, with early degenerative changes occurring on the iliac surface rather than on both surfaces of the joint simultaneously.28 Other changes associated with aging include the development of intra-articular fibrous connections.29 However, even with severe degenerative changes, the SIJ rarely fuses.21

The SIJ can be the site of manifestation for several disease processes, including SI tuberculosis, spondyloarthropathy (ankylosing spondylitis), and crystal and pyogenic arthropathies.

Joint Capsule

The SIJ capsule, consisting of two layers, is extensive and very strong. It attaches to both articular margins of the joint and is thickened inferiorly.

Ligaments

Like other synovial joints, the SIJ is reinforced by ligaments, but the ligaments of the SIJ are some of the strongest and toughest ligaments of the body.

Anterior Sacroiliac (Articular)

The anterior sacral ligament (Fig. 29-2) is an anteroinferior thickening of the fibrous capsule, which is relatively weak and thin compared with the rest of the SI ligaments. The ligament extends between the anterior and inferior borders of the iliac auricular surface and the anterior border of the sacral auricular surface.21 The anterior sacral ligament is better developed near the arcuate line and the posterior inferior iliac spine (PIIS), where it connects the third sacral segment to the lateral side of the preauricular sulcus.

Because of its thinness, this ligament is often injured and can be a source of pain. It can be palpated at Baer's SI point*30 and can be stressed using the anterior distraction and posterior compression pain provocation tests (see later).

*Baer's SI point has been described as being on a line from the umbilicus to the anterior superior iliac spine, 5 cm from the umbilicus.

Interosseous Sacroiliac (Articular)

This is a strong, short ligament located deep to the posterior (dorsal) SI ligament, and it forms the major connection between the sacrum and the innominate, filling the irregular space posterosuperior to the joint between the lateral sacral crest and the iliac tuberosity (Fig. 29-3).31 The deep portion sends fibers cranially and caudally from behind the auricular depressions. The superficial portion is a fibrous sheet connecting the superior (cranial) and posterior (dorsal) margins of the sacrum to the ilium, forming a layer that limits direct palpation of the SIJ. The interosseous SI ligament functions to resist anterior and inferior movement of the sacrum.

Posterior (Dorsal) Sacroiliac (Articular)

The posterior (dorsal) SI ligament or long ligament (see Fig. 29-3), which is easily palpable in the area directly caudal to the posterior superior iliac spine (PSIS), connects the PSIS (and a small part of the iliac crest) with the lateral crest of the third and fourth segments of the sacrum.18 This is a very tough and strong ligament. The fibers from this ligament are multidirectional and blend laterally with the sacrotuberous ligament. It also has attachments medially to the erector spinae32 and multifidus muscles33 and the thoracodorsal fascia. Thus, contractions of the various muscles that attach to this ligament can result in the tightening of the ligament.

Directly caudal to the PSIS, the ligament is so solid and stout that one can easily think a bony structure is being palpated. What complicates matters is the fact that the area overlying the ligament is a frequent source of pain.34

The lateral expansion of the long ligament in the region directly caudal to the PSIS varies between 15 and 30 mm. The length, measured between the PSIS and the third and fourth sacral segments, varies between 42 and 75 mm. The lateral part of the posterior (dorsal) ligament is continuous with fibers passing between ischial tuberosity and iliac bone.

At the superior (cranial) aspect, the posterior (dorsal) ligament is attached to the PSIS and the adjacent part of the ilium, at the inferior (caudal) side to the lateral crest of the third and fourth, and occasionally to the fifth, sacral segments.32

Nutation (anterior motion) of the sacrum appears to slacken the posterior (dorsal) ligament, whereas counternutation (posterior motion) tautens the ligament.32

Sacrotuberous (Extra-Articular)

This ligament (see Fig. 29-3) is composed of three large fibrous bands, broadly attached by its base to the PSIS, the lateral sacrum, and partly blended with the posterior (dorsal) SI ligament. Its oblique, lateral fibers descend and attach to the medial margin of the ischial tuberosity, spanning the piriformis muscle from which it receives some fibers. The medial fibers, running anteroinferior and laterally, have an attachment to the transverse tubercles of S3, S4, and S5, and the lateral margin of the coccyx. To the posterior surface of the sacrotuberous ligament are attached the lowest fibers of the gluteus maximus and the piriformis, the contraction of which produces increased tension in the ligament.35 Superficial fibers on the inferior aspect of the ligament can continue into the tendon of the biceps femoris.

In addition to stabilizing against nutation of the sacrum, the sacrotuberous ligament also counteracts against the posterior (dorsal) and superior (cranial) migration of the sacral apex during weight bearing.36,37

Sacrospinous (Extra-Articular)

Thinner than the sacrotuberous ligament, this triangular-shaped ligament extends from the ischial spine to the lateral margins of the sacrum and coccyx, and also laterally to the spine of the ischium (see Fig. 29-3). The ligament runs anterior (deep) to the sacrotuberous ligament to which it blends and then attaches to the capsule of the SIJ.33

The sacrotuberous and sacrospinous ligaments, which convert the greater and lesser sciatic notches into the greater and lesser foramen respectively, oppose forward tilting of the sacrum on the innominates during weight bearing of the vertebral column.

Iliolumbar (Indirect)

The anatomy of the iliolumbar ligament (Fig. 29-2) is described in Chapter 28.

Pubic Symphysis

The pubic symphysis is classified as a symphysis because it has no synovial tissue or fluid, and it contains a fibrocartilaginous lamina or disk (Fig. 29-2). The bone surfaces of the joint are covered with hyaline cartilage, but are kept apart by the presence of the disk.

The following are the supporting ligaments of this joint23:

• Superior pubic ligament, a thick fibrous band.
• Inferior arcuate pubic ligament, which attaches to the inferior pubic rami bilaterally and blends with the articular disk.
• Posterior pubic ligament, a membranous structure that blends with the adjacent periosteum.
• Anterior ligament, a very thick band that contains both transverse and oblique fibers.

The pubic symphysis is a common source of groin pain, particularly in athletes (see section “Groin Pain”).

Muscles

Lee12 lists 35 muscles that attach directly to the sacrum or innominate, or both (Table 29-1). A muscle attaching to a bone has the potential for moving that bone, although the degree of potential varies. Rather than producing movement at the SIJ, the muscles around the pelvis are more likely involved directly or indirectly in helping to provide stability to the joint.

Piriformis

This muscle (see Chap. 19) arises from the anterior aspect of the S2, S3, and S4 segments of the sacrum; the capsule of the SIJ; and the sacrotuberous ligament. It exits from the pelvis via the greater sciatic foramen, before attaching to the upper border of the greater trochanter of the femur.

The piriformis primarily functions to produce external rotation and abduction of the femur, but is also thought to function as an internal rotator and abductor of the hip if the hip joint is flexed beyond 90 degrees. It also helps to stabilize the SIJ, although too much tension from it can restrict the motion of this joint.38 The piriformis has been implicated as the source for a number of conditions in this area, including the following two:

• Entrapment neuropathies of the sciatic nerve (piriformis syndrome.39–45).Piriformis syndrome is described in Chapter 5.
• Trigger and tender points.46

Transversus Abdominis

For a detailed description of the anatomy of the transversus abdominis (TrA), refer to Chapter 28. Although the TrA does not cross the SIJ directly, it can affect the stiffness of the pelvis through its direct anterior attachments to the ilium, as well as its attachments to the middle layer and the deep laminae of the posterior layer of the thoracodorsal fascia.47,48

Multifidus

The anatomy of the multifidus muscle is described in Chapter 28. Some of the deepest fibers of the multifidus attach to the capsules of the zygapophyseal joints49 and are located close to the centers of rotation for spinal motion. They connect adjacent vertebrae at appropriate angles, and their geometry remains relatively constant through a range of postures, thereby enhancing spinal stability.50

Erector Spinae

For a detailed description of the anatomy of the erector spinae, refer to Chapter 28. Through its extending effect on the spine and its substantial sacral attachments, the erector spinae might be thought to promote sacral nutation, although this has not been proven.

Gluteus Maximus

This is one of the strongest muscles in the body (see Chap. 19). It arises from the posterior gluteal line of the innominate, the posterior aspect of the lower lateral sacrum and coccyx, the aponeurosis of erector spinae muscle, the superficial laminae of the posterior thoracodorsal fascia, and the fascia covering the gluteus medius muscle, before attaching to the gluteal tuberosity. In the pelvis, the gluteus maximus blends with the ipsilateral multifidus, through the raphe of the thoracodorsal fascia,33 and the contralateral latissimus dorsi, through the superficial laminae of the thoracodorsal fascia.51 Some of its fibers attach to the sacrotuberous ligament. When these fibers contract, tension in the sacrotuberous ligament increases.52

Iliacus

This muscle arises from the iliac fossa (see Chap. 19), the iliac crest, the anterior SI ligament, the inferior fibers of the iliolumbar ligament,53 and the lateral aspect of the sacrum. As it travels distally, its fibers merge with the lateral aspect of the psoas major tendon to form the iliopsoas, which continues onto the lesser trochanter of the femur, sending some fibers to the hip joint capsule as it passes.

Long Head of the Biceps Femoris

The long head of the biceps femoris originates from the ischial tuberosity and sacrotuberous ligament. In addition to functioning as a hip extensor and knee flexor, the long head of the biceps femoris, due to its connections to the sacrotuberous ligament, may also have a proprioceptive role during activities such as gait.

Pelvic Floor Musculature

The term “pelvic floor muscles” primarily refers to the levator ani, a muscle group composed of the pubococcygeus, puborectalis, and iliococcygeus. The levator ani muscles join the coccygeus muscles to complete the pelvic floor. The pelvic floor muscles work in a coordinated manner to increase intra-abdominal pressure, provide rectal support during defecation, inhibit bladder activity, help support the pelvic organs, and assist in lumbopelvic stability.54

Levator Ani

The levator ani (Fig. 29-4) originates anteriorly from the pelvic surface of the pubis, posteriorly from the inner surface of the ischial spine, and from the obturator fascia. It inserts into the front and sides of the coccyx, to the sides of the rectum, and into the perineal body. The levator ani forms the floor of the pelvic cavity, functions to constrict the lower end of the rectum and vagina, and can also be activated during forced expiration.

The muscle, which consists of anterior, intermediate, and posterior fibers, is innervated by the muscular branches of the pudendal plexus.

Anterior Fibers

The anterior fibers insert into the perineal body, comprise the levator prostatae or sphincter vaginae, and form a sling around the prostate or vagina.

Intermediate Fibers

• Puborectalis. The puborectalis (see Fig. 29-4) originates at the pubis and forms a sling around the junction of the rectum and the anal canal. The muscle pulls the anorectal junction anteriorly, assisting the external sphincter in anal closure.
• Pubococcygeus.The pubococcygeal muscle (see Fig. 29-4) arises from the pubis and its superior ramus, and passes posteriorly to insert into the anococcygeal body between the coccyx and the anal canal. The muscle functions to pull the coccyx forward. It also serves to elevate the pelvic organs and compress the rectum and vagina.

Posterior Fibers

The iliococcygeal muscle (see Fig. 29-4) arises from the arcus tendineus and ischial spine and inserts onto the last segment of the coccyx and the anococcygeal body. The muscle functions to pull the coccyx from side to side and to elevate the rectum.

• Levator Plate. The pubococcygeal muscle and the iliococcygeal muscle unite posterior to the anorectal junction to form the levator plate, which inserts into the coccyx.
• Coccygeus. This muscle (Fig. 29-4) arises from the pelvic surface of the ischial spine and sacrospinous ligament and inserts on the coccyx margin and side of the lowest segment of the sacrum. Supplied by the muscular branches of the pudendal plexus, the coccygeus functions to pull forward and support the coccyx. In addition, the coccygeus muscle provides support for the pelvic contents and the SIJ.

Neurology

It remains unclear precisely how the anterior and posterior aspects of the SIJ in humans are innervated, although the anterior portion of the joint likely receives innervation from the posterior rami of the L2 to S2 roots.55 Contribution from these root levels is highly variable and may differ among the joints of given individuals.56 Additional innervation to the anterior joint may arise directly from the obturator nerve, superior gluteal nerve, or lumbosacral trunk.24,57 The posterior portion of the joint is likely innervated by the posterior rami of L4 to S3, with a particular contribution from S1 and S2.58 An additional autonomic component of the joint's innervation further increases the complexity of its neural supply and likely adds to the variability of pain referral patterns from this area.57,59

Motions at the neighboring lumbar spine predominantly occur around the sagittal plane and comprise flexion and extension, whereas the motions occurring at the hip occur in three planes and include the one motion that the lumbar spine does not tolerate well, i.e., rotation. Thus, the pelvic area must function to transfer the loads generated by body weight and gravity during standing, walking, sitting, and other functional tasks.60 To date, there is very little agreement, either among or even within disciplines, about how the structures of the pelvis achieve this. For many decades, it was thought that the SIJ was immobile due to the close fitting nature of the articular surfaces. Research has now shown that mobility of the SIJ is not only possible61–64 but also essential for shock absorption during weight-bearing activities.65 However, the range of motion in the SIJ is small, less than 4 degrees of rotation and up to 1.6 mm of translation.62,66 Of interest, is the fact that one study67 found no difference in available range of motion between the symptomatic and asymptomatic sides.

It is likely that the movement of the pelvis is in the nature of deformations and slight gliding motions around a number of undefined axes, with the joints of the pelvic ring deforming in response to body weight and ground reaction forces. The amplitude of this motion likely varies between individuals. Motion at the SIJ is facilitated by several features, including the following:

• The fibrocartilaginous surfaces of the innominate facets, which are deformable, especially during weight bearing, when the surfaces are forced together.
• The pubic symphysis—if the innominates are moving at the SIJ, then they must also be moving at their anterior junction, which would allow for an immediate, and almost perfect, reciprocal motion.

No manual diagnostic tests have shown reliability for determining how much an individual's SIJ is moving in either symptomatic or asymptomatic subjects. In contrast to Sturesson's study,67 when Doppler imaging testing has been used to measure stiffness (or laxity) of the SIJ in subjects with and without pelvic pain, it has been shown that asymmetry of stiffness between sides correlated with the symptomatic individual.68–70 These studies have shown that within the same subject, asymptomatic individuals have similar values for the left and right SIJs, whereas individuals with unilateral posterior pelvic girdle pain had different stiffness values for the left and right sides. Theoretically, when assessing SIJ mobility, a dysfunction at the SIJ can manifest as one of the two types of asymmetries:

• If one of the SIJs is hypermobile, the amplitude of motion is asymmetrically increased and the resistance to motion is decreased on the dysfunctional side.
• If one of the SIJs is hypomobile, the amplitude of motion is asymmetrically reduced and the resistance to motion is increased on the dysfunctional side.

Thus, the current trend is to focus more on the symmetry, or asymmetry, of the motions palpated or observed.

Anatomical research,12,71,72 initiated to determine the source of low back pain, has demonstrated that alterations in the pattern of muscular contraction and the timing of specific muscle activation differ between healthy subjects and those demonstrating symptoms. Furthermore, studies73 have shown that the strength and endurance of the trunk muscles is important in determining the muscle capacity of individuals. This research has led to theories about the force- and form-closure mechanisms of joints and how stability is necessary at joints for effective load transfer. Based on this knowledge, functional tests of load transfer through the pelvic girdle have been developed74–76 together with a number of treatment protocols.77–79 This approach has three physical components (form closure, force closure, and motor control), and one psychological component (emotions).

In upright positions, the SIJ is subjected to considerable shear force as the mass of the upper body must be transferred to the lower limbs via the ilia.80,81 The body has two mechanisms to overcome this shear force: one dependent on the shape and structure of the joint surfaces of the SIJs (form closure), which is wedge shaped with a high coefficient of friction, and the other mechanism involving generation of compressive forces across the SIJ via muscle contraction (force closure).81

Form Closure

Form closure refers to a state of stability within the pelvic mechanism, with the degree of stability dependent on its anatomy, with no need for extra forces to maintain the stable state of the system.72 The following anatomic structures are proposed to assist with form closure:

• The congruity of the articular surfaces and the friction coefficient of the articular cartilage. Both the coarseness of the cartilage and the complementary grooves and ridges increase the friction coefficient, and thus contribute to form closure by resisting against horizontal and vertical translations.24 In infants, the joint surfaces are very planar, but between the ages of 11 and 15 years, the characteristic ridges and humps that make up the mature sacrum begin to form. By the third decade, the superficial layers of the fibrocartilage are fibrillated and crevice formation and erosion has begun. By the fourth and fifth decades, the articular surfaces increase irregularity and coarseness and the wedging is incomplete.21
• The integrity of the ligaments.
• The shape of the closely fitting joint surfaces.

According to current research, when the sacrum nutates, or flexes, relative to the innominate (Fig. 29-5), or when the innominate posteriorly rotates relative to the sacrum, the greatest number of ligaments, particularly the interosseous and posterior (dorsal) ligaments, are tightened at the SIJ.72,82,83 These latter ligaments lie posterior to the joint and approximate the posterior iliac bones when placed under tension.82 Thus, nutation of the sacrum can be described as the close packed position, or self-locking mechanism, for the SIJ and is, therefore, the most effective position for transferring high loads. This position somewhat conveniently produces a position of lumbar lordosis, which is advocated in many interventions for the lumbar spine.

Just as nutation of the sacrum enhances the self-locking mechanism, counternutation of the sacrum (Fig. 29-6), which occurs during activities such as the end range of forward bending, sacral sitting, long sitting, and hip hyperextension, reduces the self-locking mechanism.82 This position results in a loss of the lumbar lordosis and an increase in intervertebral disk pressure (see Chap. 28).

Using forward bending at the waist as an example, a combination of anterior and outward rotation of both innominates results in the approximation and superior motion of both PSISs, while the sacrum nutates (Table 29-2). After approximately 60 degrees of forward bending, the innominates continue to rotate anteriorly, but the sacrum no longer nutates.12 If the sacrum remains nutated throughout the forward bending, the SIJ remains compressed and stable. However, if the sacrum is forced to counternutate earlier in the range, as in individuals with tight hamstrings, less compression occurs, thereby increasing the reliance on dynamic stabilization provided by muscles and thus making the SIJ more vulnerable to injury.12

Force Closure

Force closure requires intrinsic and extrinsic forces to keep the SIJ stable.72 These dynamic forces involve the neurological and myofascial systems and gravity. Together, these components produce a self-locking mechanism for the SIJ. Optimum force closure requires application of just the right amount of force at just the right time, which in turn requires a motor control system that can predict the timing of the load and prepare the system appropriately. The degree of force closure depends on the capability of an individual's form closure and the various loading conditions (e.g., speed, duration, magnitude, and predictability).84

In a kinetic analysis of the pelvic girdle, Vleeming and colleagues51,82 identified a number of muscles that resist translational forces and which are specifically important to the force-closure mechanism: the erector spinae, gluteus maximus, latissimus dorsi, and biceps femoris (see Chap. 28). Two other muscle groups, an “inner muscle unit” and an “outer muscle unit” also play an important role.12,73,79 The inner muscle unit consists of the following:

• Transversus abdominis (TrA). A study by Richardson and colleagues85 found that contraction of the TrA significantly decreases the laxity of the SIJ, and that this decrease in laxity is larger than that caused by a bracing action using all the lateral abdominal muscles. Theoretically, contraction of the TrA produces a force that approximates the ilia anteriorly.85
• The muscles of the pelvic floor. Hemborg and colleagues86 have demonstrated that the pelvic floor muscles coactivate with the TrA during lifting tasks.
• Multifidus. Studies87–89 have reported that the deep fibers of the multifidus become inhibited and reduced in size in individuals with low back and pelvic girdle pain.

The outer muscle unit consists of four systems: the posterior oblique system (latissimus dorsi, gluteus maximus, and thoracolumbar fascia), the deep longitudinal system (erector spinae, deep lamina of the thoracolumbar fascia, sacrotuberous ligament, and biceps femoris), the anterior oblique system (external and internal oblique, contralateral adductors of the thigh, and the intervening anterior abdominal fascia), and the lateral system (gluteus medius–minimus and contralateral adductors of the thigh). The outer muscle unit is proposed to contribute to the force-closure mechanism in the following manner12:

• Posterior oblique system. The gluteus maximus (see Chap. 19), which blends with the thoracodorsal fascia, and the contralateral latissimus dorsi contribute to force closure of the SIJ posteriorly by approximating the posterior aspects of the innominates. This oblique system is a significant contributor to load transference through the pelvic girdle during the rotational activities of gait.
• Deep longitudinal system. This system serves to counteract any anterior shear or sacral nutation forces as well as to facilitate compression through the SIJs. As mentioned in the anatomy section, the long head of the biceps femoris muscle controls the degree of nutation via its connections to the sacrotuberous ligaments.36
• Anterior oblique system. The oblique abdominals, acting as phasic muscles, initiate movements79 and are involved in all movements of the trunk and upper and lower extremities, except when the legs are crossed.90
• Lateral system. The lateral system functions to stabilize the pelvic girdle on the femoral head during gait through a coordinated action.

As alluded to earlier, the sacral positions that correspond to poor sacral biomechanics are very similar to those lumbar spine positions that are unfavorable for spinal stability. Conversely, the positions that enhance sacral stability also enhance lumbar spine stability. As a result, there has been much confusion amongst disciplines when determining whether the SIJ or lumbar spine is the cause of the patient's symptoms. For example, consider the prone on elbows position (see Chap. 28), which nutates the sacrum and increases the lordosis of the lumbar spine. If a patient with either a sacral dysfunction or an intervertebral disk herniation is asked to adopt this position, the symptoms would likely decrease.

Most investigators agree that no single test can be used to confirm the diagnosis of SIJ dysfunction because of the complexity of the anatomy and biomechanics and its proximity to other symptom-provoking structures.

Diagnostic physical examination tests that are commonly used to determine a diagnosis include56

• direct tenderness;
• soft tissue examination for zones of hyperirritability and tissue texture changes;
• evaluation of referral zones;
• associated fascial or musculotendinous restrictions;
• regional abnormal length–strength muscle relationships;
• postural analysis;
• true leg length and functional leg length determination;
• static and dynamic osseous landmark examinations;
• provocative testing, including traditional orthopaedic tests, motion demand tests, and ligament tension tests.

Although traditionally assumed to be reliable and diagnostically useful, none of these tests has ever been validated against an independent criterion standard.56 As a consequence, controversy exists about which group of tests is the best.

Under the premise that a relationship exists between pelvic asymmetry and low back pain, orthopaedic, osteopathic, and physical therapy tests promote the use of pain provocation (symptom based) tests and static (positional) or dynamic (motion or functional) tests.1,10,12,38,92–95

The use of static tests has been questioned as,96–100 although Cibulka and colleagues101 found the results from these tests reliable, Levangie100 found a weak association between standing PSIS asymmetry and low back pain, at least in selected groups. The problems with static testing are

• determining whether the asymmetry noted is normal or abnormal;
• determining which side is abnormal;
• determining whether the asymmetry is too asymmetric or not asymmetric enough. For example, if the right innominate is anteriorly rotated, compared with the left, is it rotated too much, too little, or just the right amount compared with its starting position? Because the starting position is not known, the degree of rotation cannot be assessed.

The dynamic tests do not fair much better. Dreyfuss and colleagues56 reported 20% positive findings in one or more of the dynamic (motion or functional) tests in a group of asymptomatic people. An example of a dynamic test is the standing flexion test, which has been used frequently to analyze SIJ mobility and to determine the side of the impairment. The test is performed as follows: Each PSIS is palpated with the thumb placed under it caudally. The patient then bends forward at the waist. Provided there is no impairment in the SIJ or the lower lumbar spine, as the patient bends forward, both thumbs should move superiorly (cranially). If one SIJ joint is “blocked,” it moves upward further in relation to the other side.99 Thus far, reliability studies of the standing flexion test show that it lacks sufficient diagnostic power.99,102,103 This shortfall may be because the compression of the joints caused by the sacral nutation in the early to midranges of forward flexion likely limits movement of the SIJ.104

Some studies have reported that pain provocation tests have a good interexaminer reliability,99,105 but they have not been found reliable by others.17,102 This is likely because the pain provocation tests have only been found reliable in identifying SIJ dysfunction in certain populations, such as patients with posterior pelvic pain during or following pregnancy.106

As several recent studies have found improved interrater reliability in the diagnosis of low back pain when using a combination of physical examination procedures as opposed to a single model approach,17,56,99,107,108 it would be logical to assume that a similar approach would work with the SIJ.

Ideally, the diagnosis needs to be based on the results from a thorough biomechanical examination that includes an assessment of load transfer, and pain provocation. Patients with failed load transfer through the pelvic girdle often present with inappropriate force closure, in that certain muscles become overactive while others remain inactive, delayed, or asymmetrical in their recruitment.109 When approaching SIJ dysfunction it is likely more important to determine why there are symptoms, rather than attempting to identify the specific symptom generating structures.

In most cases, an examination of the pelvic joints is of little use if the lumbar spine and the hip joints have not been previously cleared by examination or intervention, because both of these joints can refer pain to this area and may also profoundly affect the function of the SIJ. The algorithm depicted in Fig. 29-7 should serve as a guide.

History

A history of low back pain or leg pain, or both, warrants an examination of the lumbopelvic–hip complex. The most common presenting symptoms in patients with SIJ dysfunction are pain or tenderness over the region of the posterior superior iliac spine.110–112

Mechanical pain resulting from SIJ dysfunction may manifest as sacral pain but may also refer pain distally. For example, SIJ problems can refer pain to the iliac fossa, the buttock, the groin, the superior lateral and posterior thigh, and rarely below the knee.113 In general, SIJ pain is characterized by unilateral pain below the level of L5, in the absence of midline pain, whereas irritation of a spinal nerve may cause radicular symptoms below the knee.114 Pubic symphysis dysfunction typically results in localized pain, or groin pain, which is aggravated by activities involving the hip adductor or rectus abdominis muscles.115 However, studies have shown that using evidence of pain referral patterns, or evidence of groin pain are neither sensitive nor specific for SIJ dysfunction.116

Pain also may be referred to the sacrum from a distant structure, including the contralateral sacrospinalis muscle,117 the ipsilateral interspinous ligaments of L3 to S2,118 and the L4 to L5 facet joints.119 In addition, it is well established that dysfunctional pelvic floor muscles can contribute to the symptoms of interstitial cystitis and the so-called urethral syndrome, which is urgency–frequency with or without chronic pelvic pain.120–122

The following findings are likely to be present with a SIJ dysfunction:13,56,123,124

• A history of sharp pain that occurred with a particular activity and that awakens the patient from sleep upon turning in bed.
• Pain with walking, ascending or descending stairs, or hopping or standing on the involved leg.
• Pain with forward bending of the trunk and pain with standing hip flexion.
• Pain with transitional movements such as rising to stand from a sitting position or getting in and out of the car.
• Pain with a straight leg raise at, or near, the end of range (occasionally early in the range when hyperacute).
• Pain and sometimes limitation on extension and ipsilateral side bending of the trunk.
• Pain that is worsened with long periods of sitting or standing if the lumbar lordosis is not maintained.

Systems Review

Given the number of visceral organs in the vicinity of the SIJ, the clinician must complete a thorough systems review to rule out a visceral source for the symptoms. A Cyriax scanning examination (see Chap. 4) should be performed on any patient who presents with an insidious onset of pelvic pain. The scanning examination, which includes the primary stress tests (anterior and posterior distraction), can be used to help detect sacroiliitis resulting from microtraumatic arthritis, macrotraumatic arthritis, or systemic arthritis (e.g., ankylosing spondylitis, Reiter's syndrome), or the more serious pathologies grouped under the sign of the buttock (see Chap. 19). Primary breast, lung, and prostate cancers are among the most common cancers to metastasize to the axial skeleton, including the pelvic ring.125 A further source of sacral pain can be a stress fracture of the sacrum, which can be associated with a wide range of extrinsic and intrinsic risk factors (see “Intervention Strategies”), and an equally wide range of symptoms and signs.126

Tests and Measures

As previously mentioned, in order to rule in or rule out SIJ dysfunction, a thorough musculoskeletal examination of the low back, the pelvis, the hips, and the remainder of the lower extremities, including a full neurologic evaluation must be performed.

Observation

The observation should begin with an overall assessment of posture to check for the presence of asymmetry. The clinician should observe the degree of tilt at the pelvis. The question of cause and effect should be raised. An anterior pelvic tilt causes an increase in the lumbar lordosis and thoracic kyphosis. The anterior pelvic tilt results in a stretching of the abdominals and the sacrotuberous, SI, and sacrospinous ligaments, and an adaptive shortening of the hip flexors, the hamstrings, and the erector spinae. In contrast, a posterior pelvic tilt results in lengthening of the hip flexors, the hamstrings, and the erector spinae, and adaptive shortening of the abdominals and the gluteals.

A lateral pelvic tilt, in which one iliac crest is higher than the other, may be caused by scoliosis with ipsilateral lumbar convexity, a leg length discrepancy, or shortening of the contralateral quadratus lumborum. This position results in adaptive shortening of the ipsilateral hip abductors and contralateral hip adductors, and weakness of the contralateral hip abductors.

There appears to be a strong correlation between the position of the pelvis and the forward head.127 If the pelvic landmarks are asymmetric and the patient has a forward head, the clinician should attempt to correct the forward head. If the attempted correction of the forward head worsens the pelvic asymmetry and increases the symptoms, the intervention should be aimed at correcting the asymmetry. If the attempted correction of the forward head improves the pelvic asymmetry and the symptoms, the subsequent intervention should be aimed at correcting the forward head.128

Hip Range of Motion

Range of motion of the hip, including internal and external rotation, is performed to help rule out pain referred from the hip joint. Although a unilateral limitation of hip motion, in which one of the motions is unequal between the left and right sides, has been observed in patients with disorders of the SIJ,64,129–131 the evidence to demonstrate whether hip motion is limited in patients with signs of SIJ dysfunction is inconclusive. LaBan and colleagues115 noted asymmetry in hip abduction and external rotation in patients with inflammation of the SIJs. Dunn and colleagues132 reported limited hip mobility in patients with infection of the SIJ; however, no mention was made as to which movements were limited.

Others have described cases in which patients with low back pain had unilateral, limited internal hip rotation and excessive external hip rotation, and also exhibited signs of SIJ dysfunction. A recent study by Cibulka and colleagues129 attempted to determine whether a characteristic pattern of hip range of motion existed in patients with low back pain, and whether those classified as having SIJ dysfunction have a different pattern of hip range of motion compared with those with unspecified low back pain. The study found that patients with low back pain, who had signs suggesting SIJ regional pain, had significantly more hip external than internal rotation range of motion on one side. The authors concluded that identifying unilateral hip range of motion asymmetry in patients with low back pain may help in diagnosing SIJ regional pain.129

Landmark Palpation

The palpation of landmarks can be used to locate areas of tenderness rather than for detecting pelvic asymmetry, because as pelvic landmark asymmetry is probably the norm, “positive” findings are likely to be misleading.100 The various landmarks of the pelvis are palpated with the patient positioned standing, sitting, and lying (see Figs. 29-8 and 29-9).

The following landmarks and structures are palpated with the patient standing:

• Iliac crest. The iliac crests on both sides are located using the medial aspects of the index fingers. The crest heights should be level.
• Anterior superior iliac spine (ASIS). These structures are located anteriorly to the iliac crests. Tenderness of the ASIS may indicate a so-called hip pointer injury or injury to the inguinal ligament. An inferior ASIS relative to the other side may indicate a rotated innominate.8 According to osteopathic doctrine, if the innominate is anteriorly rotated in the supine position, the leg will be longer on that side, but if posteriorly rotated, the leg will be shorter.8 However, a study by Levangie100 found that pelvic asymmetry was not positively associated with low back pain in any way that seemed clinically meaningful. It has been suggested to assess the ASIS in sitting versus standing, but there are no reliable studies to recommend this method.
• Posterior superior iliac spine (PSIS). These structures are located posteriorly to the iliac crests and approximately 2–3 cm beneath the dimples of the lumbar spine and level with the S2 spinous process. Slightly medially and distal to the PSIS are the SIJs. To assess the levels of the PSIS relative to the opposite side, the clinician hooks the thumbs under both PSIS. A superior PSIS relative to the other side may indicate a rotated innominate.8 A study by Levangie100 found that although pelvic asymmetry was not positively associated with low back pain in any way that seemed clinically meaningful, asymmetry of PSIS landmarks showed some evidence of a weak positive association with low back pain. This would indicate that the test does not qualify as a screening tool. PSIS asymmetry can also be assessed similarly in sitting, but the findings from Levangie100 indicate that this test provides little value during the examination and does not qualify as a screening tool.
• Pubic symphysis and pubic tubercles. The pubic tubercles are lateral to the pubic symphysis.
• Posterior (dorsal) ligament. This strong ligament is situated in a deep depression between the sacrum and ilium.
• Ischial tuberosity and the sacrotuberous ligament (medial to the tuberosity). According to osteopathic doctrine, the sacrotuberous ligament is firm on the side of an anteriorly rotated innominate, and taut on the side of a posteriorly rotated innominate.8 The patient is positioned prone, and the clinician stands at the patient's side. With the heel of the hands, the clinician locates the ischial tuberosities through the soft tissue at the gluteal folds. Then, with the thumbs, the clinician palpates the inferomedial aspect of the ischial tuberosities. From this point, the clinician slides the thumbs superolaterally and palpates the sacrotuberous ligament. The clinician then compares the relative tension between the left and right sides.
• Sacral sulcus (sacral base).The sacral sulcus (dimple) is located over the sacral base. From the PSIS, the clinician moves in a thumb width and then up a thumb width.
• Inferior lateral angle (ILA). These structures are level with the prominent part of the tailbone.
• L5 segment. The clinician palpates medially along the iliac crest. L5 is usually level with the point at which the palpating finger begins to descend on the crest. The L5–S1 zygapophyseal joints are located halfway between the L5 spinous process and the ipsilateral PSIS.
• Lumbosacral angle.An increased or decreased lumbosacral angle (the angle the sacrum makes with the lumbar spine) on one side may indicate a rotated innominate. Although very difficult to measure without radiographs, the normal lumbosacral angle is approximately 140 degrees from the vertical.
• S2 segment. S2 is normally level with the PSIS.

Functional Tests of Load Transfer through the Pelvis

Forward Bending

This test assesses the ability of the pelvis to tolerate both vertical and horizontal shear forces, and its ability to control forward sagittal rotation during forward bending of the trunk. When the leg lengths are equal, the sacrum should nutate bilaterally relative to the innominates and remain nutated throughout the forward bending motion as the pelvic girdle flexes symmetrically at the hip joints.104 The patient is positioned in standing and is asked to bend forward at the waist while the clinician observes the lumbopelvic hip rhythm (Fig. 29-10). A positive test for inadequate load transfer is if there is a lack of anterior pelvic tilt, excessive flexion of the thoracolumbar spine, and any twisting that occurs in the pelvic girdle.84 Although asymmetry of motion of the innominate during forward bending is a positive finding, it is not indicative of any specific dysfunction of the SIJ.

Test for Form Closure

The patient is positioned in supine with the hips and the knees slightly flexed or supported over a bolster. Since muscle activation can compress the SIJ, the patient is instructed to completely relax during the test. The following description is for a test of the right side of the sacrum. With the right hand, the clinician grasps the anterior aspect of the patient's right innominate and ASIS (Fig. 29-11). The clinician then slides his or her left hand under the left side of the patient's lumbar spine and palpates the left sacral sulcus, just medial to the PSIS with the index and long finger to monitor translation between the sacrum and the innominate. From this position, the clinician stabilizes the left sacral base and sulcus with the left hand, and pushes the right innominate down toward the bed using the right hand, in a variety of directions to determine the plane of the SIJ. Slight motion should be felt before a ligamentous end-feel is reached. Once the plane of motion is determined, the stiffness for A-P translation of the SIJ is compared bilaterally. There should be no pain or asymmetry. A loss of motion or pain reproduction compared with the contralateral side indicates dysfunction. To test the ability of the pelvic girdle to resist vertical translation, a superoinferior force is applied to the innominate through the distal end of the femur or through the ischial tuberosity (Fig. 29-12). Again, slight motion should be felt (although a little more than with the previous test) before a solid ligamentous end-feel is reached. The stiffness for superoinferior translation of the SIJ is compared bilaterally. There should be no pain or asymmetry. A loss of motion or pain reproduction compared with the contralateral side indicates dysfunction.

Tests for Force Closure and Motor Control

The active straight leg raise (ASLR) test and the reverse ASLR have been recommended as tests to help identify nonoptimal stabilization of the pelvic girdle and the ability to transfer loads between the lumbosacral spine and legs.

• The ActiveStraight Leg Raise (ASLR). The ASLR demonstrates the patient's ability to transfer load to the pelvis in the supine line position and has been validated for reliability, sensitivity, and specificity of pelvic girdle pain after pregnancy.75,76,133 It can also be used to identify non-optimal stabilization strategies for load transfer through the pelvis.84 The test is performed with the patient in supine with both legs straight. The patient is instructed to lift one leg off the table without bending the knee and the clinician observes the strategy used (Fig. 29-13). The leg should flex at the hip joint and the pelvis should not rotate, side bend, flex, or extend relative to the lumbar spine. The ribcage should not draw in excessively (over activation of the external oblique muscles), nor should the lower ribs flare out excessively (over activation of the internal oblique muscles), or the abdomen bulge (Valsalva). If the patient is unable to perform this maneuver correctly, or the maneuver causes pain, the test is repeated with the clinician applying a compression force through the pelvis (anterior then posterior) directed at the SIJs (form closure) (Fig. 29-14). If the patient is then able to perform the ASLR, the test is considered positive. If the application of anterior compression enabled the patient to perform the ASLR, an exercise program emphasizing the isolation, timing, and strength of the TrA is recommended. If the application of posterior compression enabled the patient to perform the ASLR, an exercise program emphasizing the isolation, timing, and strength of the multifidus is recommended. Slight modifications to the test can be used to help confirm the diagnosis.
  • One knee is flexed, and the patient is asked to perform a straight leg raise with the other leg. Flexing the contralateral knee to the straight leg raise has the effect of relaxing the lumbar spine while maintaining the counternutation on the ipsilateral side. If this maneuver decreases the pain, a muscle imbalance could be present (quadratus lumborum, multifidus, etc.).
  • The patient is asked to lift one shoulder off the bed against manual resistance from the clinician, while performing the straight leg raise on the contralateral side. This maneuver tests the ability of the anterior oblique system (force closure).

Assessment findings that indicate excessive compression include84

• reduced movement on active mobility tests;
• an ASLR test result that does not change all that worsens with compression;
• palpable hypertonicity in specific muscles and/or nonoptimum patterns of muscle recruitment during movement or in response to verbal cueing.

Assessment findings that indicate poor motion control include84

• an ASLR test result that improves with compression
• nonoptimum pattern of muscle recruitment in response to verbal cueing
• loss of joint position during functional load transfer tests.
• The reverse ASLR. This test is performed with the patient in prone with the patient performing active hip extension with the leg straight under three progressive conditions:
  • The patient performs hip extension with the leg straight (Fig. 29-15)
  • The patient performs hip extension with the leg straight with the clinician applying manual compression to the innominate bones (form closure) (Fig. 29-16).
  • The patient performs hip extension with the leg straight with the clinician resisting extension of the contralateral medially rotated upper extremity (force closure).

No diagnostic accuracy studies have been performed to determine the sensitivity and specificity of this test.

Special Tests

Sacroiliac Joint Stress Tests

A positive stress test is one that reproduces unilateral or bilateral SI pain, either anteriorly or posteriorly.134 A positive stress test indicates the presence of inflammation, but does not give any information as to the cause. If either test is positive in a patient who has recently fallen, there is a possibility that a fracture of the pelvis exists.135 Some of the stress tests are considered to have fair reliability and moderate specificity.

Anterior Sacroiliac Joint Stress Test. The anterior stress test, also called the gapping test, is performed with the patient supine. The clinician stands to one side of the patient and, crossing the arms, places the palm of the hands on the patient's anterior superior iliac spines (Fig. 29-17). The crossing of the arms ensures that the applied force is in a lateral direction, thereby gapping the anterior aspect of the SIJ. The stress is maintained for 30 seconds once an end-feel is obtained. The procedure stresses the anterior (ventral) ligament and compresses the posterior aspect of the joint. A positive test is one in which the patient's groin or SIJ pain is reproduced anteriorly, posteriorly, unilaterally, or bilaterally.

The anterior gapping test and its posterior counterpart (see next section) are believed to be sensitive for severe arthritis or anterior (ventral) ligament tears of the SIJ,134 although they have been shown to be poorly reproducible.99

Posterior Sacroiliac Joint Stress Test

The posterior stress test, also called the compression test, is performed with the patient in the supine or sidelying position. The clinician, standing behind the patient, applies a medial force to both innominates, using both hands (Fig. 29-18). The stress is maintained for 30 seconds once an end-feel is obtained. The procedure creates a medial force that tends to gap the posterior aspect of the SIJ, while compressing its anterior aspect. The reproduction of pain over one or both of the SIJs is considered a positive test. The test also indirectly assesses the ability of the sacrum to counternutate.

The posterior (dorsal) SI ligament, which is accessible just below the posterior inferior iliac spine, should be palpated for tenderness.32

Thigh Thrust (Sacrotuberous Stress Test, 4 P Test, Posh Test, Oostagard Test)

This maneuver should only be performed on a normal hip joint. The patient is positioned in supine and the resting symptoms are assessed. The clinician stands on the painful side. The clinician flexes the hip on the painful side to 90 degrees and neutral adduction, and then places his or her hand under the sacrum to form a stable base for the sacrum. The clinician then applies a downward pressure through the femur to force a posterior translation of the innominate and the patient's symptoms are assessed (Fig. 29-19). A positive test is reproduction of the patient's symptoms (posterior to the hip or near the SIJ) on the side of the loaded femur. This is one of the few SI tests that exhibits a fair sensitivity. In a study by Broadhurst and Bond,136 the test was found to have a sensitivity of 80% and a specificity of 100%.

Mennell's Test

The patient is positioned in supine and the clinician positions the leg to be tested into 30 degrees of abduction and some flexion of the hip joint (Fig. 29-20) and asks the patient to hold his or her leg in this position. The clinician pushes the lower leg into, and then away from, the pelvis in a sagittal motion (extension then flexion). A positive test is reproduction of the patient's SIJ pain. Albert and colleagues137 found this test to have a sensitivity of 54–70% and a specificity of 100%.

Resisted Hip Abduction

The patient is positioned in side lying and the clinician positions the uppermost leg into full extension and 50 degrees of abduction and asks the patient to hold his or her leg in this position. The clinician then applies a force medially (into the hip adduction) while the patient resists the force isometrically (Fig. 29-21). A positive test is reproduction of SIJ pain in the superior aspect of the joint. Broadhurst and Bond,136 found the test to have a sensitivity of 87% and a specificity of 90%.

Pubic Stress Tests

138The patient is positioned supine and the clinician stands at the patient's side. With the heel of one hand, the clinician palpates the superior aspect of the superior ramus of one pubic bone, and with the heel of the other hand, palpates the inferior aspect of the superior ramus of the opposite pubic bone. Fixing one pubic bone, the clinician applies a slow, steady, inferosuperior force to the other bone and, noting the quantity and end-feel of motion, as well as the reproduction of any symptoms, the clinician then switches hands and repeats the test so that both sides are stressed superiorly and inferiorly. Albert and colleagues137 found this test to have a sensitivity of 81% and a specificity of 99% (LR+ 4.68; LR− 0.19). This test appears useful in the diagnosis of symphysiolysis.

Sacral Thrust Test

The patient is positioned prone on a firm surface, and the clinician stands at the patient's side. With one hand, the clinician palpates the inferior aspect of the sacrum in the midline (second or third spinous process of the sacrum) and reinforces this hand with the other. The clinician then applies an anterior force at S3 (Fig. 29-22) vigorously and repeatedly (up to six thrusts), and the reproduction of symptoms is noted. The test is considered positive if pain is reproduced over the SIJs or the posterior (dorsal) SI ligament, or both.139 In a study by Laslett and colleagues,105 this test was found to have a sensitivity of 63% and a specificity of 75% (LR+ 2.5; LR− 0.49) suggesting that the test provides only marginal diagnostic value when used in isolation.

Fortin Finger Test

The patient completes a pain diagram and is then instructed to point to the region of pain using only one finger. The clinician reviews the area of pain and pain diagram for consistency and then asks the patient to repeat the procedure of pointing to his or her pain. A positive test for localization of SIJ pain has three criteria:

• The patient can localize the pain with one finger.
• The area pointed to is within 1 cm of, and immediately inferomedial to, the posterior superior iliac spine.
• The patient consistently points to the same area over at least two trials.

In a study by Fortin and Falco,112 16 subjects were chosen from 54 consecutive patients by using the Fortin finger test. All 16 patients subsequently had provocation-positive joint injections validating SIJ abnormalities (sensitivity of 100%). Another study by Dreyfuss and colleagues56 found this test to have a sensitivity of 76% and a specificity of 47% (LR+ .09; LR− 1.3).

Faber or Patrick's Test

The FABER (flexion, abduction, external rotation) test is a screening test for hip (see Chap. 19), lumbar, or SIJ dysfunction, or an iliopsoas spasm.

The patient is positioned in supine and resting symptoms are assessed. The clinician places the foot of the test leg on top of the knee of the opposite leg (placing the sole of the test leg foot against the medial aspect of the opposite thigh may be more comfortable for the patient with knee pathology). The clinician then slowly lowers the test leg into abduction, in the direction toward the examining table. The clinician then provides a gentle downward pressure on both the knee of the painful side and the ASIS of the non-painful side. A positive test results in pain and/or loss of motion as compared with the uninvolved side. Having the patient demonstrate where the pain is with this test may assist with the interpretation of this test. For SI pain, the chief complaint is typically posterior. In the various studies that have assessed the sensitivity and specificity of this test, there are a wide range of values which is likely reflective of the variety of patients used in each study and the bias that results.

Seated Flexion Test (Piedallus Sign)

The test is purported by osteopaths to help distinguish between a SI lesion and an iliosacral lesion when compared with the results of the standing flexion test.5–7 The patient sits on a hard surface with the legs over the end of the table and feet supported.8 In this position, innominate motion is severely abbreviated, because sitting places the innominates near the end of their extension range. The test is performed as follows. Each PSIS is palpated with the thumb placed under it inferiorly (caudally). The patient then bends forward at the waist (Fig. 29-23). Provided there is no impairment in the SIJ or the lower lumbar spine, as the patient bends forward, both thumbs should move superiorly (cranially). If the joint is blocked, it moves superiorly further in relation to the other side.99 However, like other palpatory tests, this examination has been shown to lack reliability, have poor sensitivity, and have low specificity as a result a low false positive rate.96,137,140 In contrast, Levangie141 determined the sensitivity to be 9%, the specificity to be 93%, the positive predictive value to be 78%, and the negative predictive value to be 28%. Clearly there is need for further study. A similar test, referred to as the sitting bend over test or sitting forward flexion test, is performed in the same manner except the patient is seated on a soft surface. However, this test has demonstrated poor sensitivity, poor reliability, and, therefore, has very poor diagnostic value.140,141

Long Sit Test

According to osteopath doctrine, the long sit test is used to indicate the direction of the rotation that the innominate has adopted and is used in conjunction with the standing flexion test. After noting the side of the impairment obtained from the standing flexion test, the clinician observes whether the medial malleolus on that side moves distally or proximally during the long sit test. Rotation about a coronal axis, whose resultant movement leads to an increase in the length of a limb, is defined as extension. If it shortens the length of the limb, it is defined as flexion. Thus, if the apparent shorter leg becomes longer during the test, the innominate on that side is purportedly held in a posteriorly rotated malposition, whereas if the apparent longer leg becomes shorter during the test, the innominate on that side is allegedly held in an anteriorly rotated malposition.

The problems with this test involve the maneuver itself. To ask patients who are experiencing some degree of discomfort to raise themselves off the bed from a supine position into a long sit position without any twisting or use of the arms is unnecessarily painful. In addition, for the successful completion of the maneuver, the patient needs a minimum of 90 degrees of hip flexion and adequate hamstring length. Perhaps not surprisingly, the test has demonstrated poor reliability, questionable validity, and, therefore, may not yield useful results.137,142

Prone Knee Bending (Nachlas) Test

The patient is positioned in prone and the clinician, while stabilizing the pelvis, flexes the knee so that the heel is brought toward the buttocks (Fig. 29-24). If pain is felt in the front of the thigh before full range is reached, the problem is in the rectus femoris muscle; if the pain is in the lumbar spine, the problem is in the lumbar spine (usually the L3 nerve root). If the problem is a hypomobile SIJ, the ipsilateral pelvic rim (palpated at the ASIS) will be felt to rotate forward.143 Leboeuf144 found this test to have a specificity of 83% and a sensitivity of 44% (LR+ 2.59; LR− 0.67). Riddle and colleagues142 found this test to have an interrater reliability of 0.26.

Leg Length Tests

These are usually performed as part of the bony landmark examination. Theoretically, posterior rotation of the innominate on the sacrum results in a decrease in leg length, as does an anterior rotation of the innominate on the contralateral side.146 Although not exact measurements of leg length, these tests can highlight any significant asymmetries.

Prone Test

Chiropractors assess leg length with the patient prone. The comparative lengths of the legs are compared by observing the heels or the medial malleoli. If a discrepancy is noted, the knees are flexed to 90 degrees while maintaining neutral hip rotation, and the landmarks are reassessed to screen for a shortened tibia. The patient is then positioned supine, and the leg lengths are reassessed using the same landmarks. Finally, the leg lengths are assessed using the long sit test. Functional leg length inequality that is secondary to SI subluxation or dysfunction may reverse from the supine to sitting position, whereas anatomic leg length inequality or functional inequality secondary to dysfunction at other sites likely will not.146

Standing Leg Length Test

The iliac crest palpation and book correction (ICPBC) method for assessing leg length is used in many clinics. The patient stands with the feet shoulder-width apart. The clinician palpates the iliac crests and compares the relative heights for asymmetry. The asymmetry identified is corrected using a book opened to the required number of pages. The iliac crest heights are reassessed. If the iliac crests are level, the thickness of the book correction is measured. One study with 34 healthy subjects found the ICPBC technique for measuring leg length discrepancy to be highly reliable and moderately valid when there is no history of pelvic deformity and the iliac crests can be readily palpated.147

Functional Leg Length

The patient stands with the feet shoulder-width apart. The clinician palpates the iliac crests, the ASISs, and the PSISs and compares the relative heights for asymmetry. The patient is then positioned with the subtalar joints in neutral, the toes pointing forward, and the knees fully extended. The same landmarks are reassessed. If the second position corrects any asymmetry found in the first position, the test is positive for a functional leg length discrepancy and indicates that the leg is structurally normal but has abnormal joint mechanics.

Sign of the Buttock

The test for this syndrome is described here because its underlying pathologies occur in the lower quadrant The sign of the buttock is not a single sign, as the name would suggest, but rather a collection of signs indicating that a serious pathology is present posterior to the axis of flexion and extension in the hip (see Chap. 19). Among the causes of the syndrome are osteomyelitis, infectious sacroiliitis, fracture of the sacrum or pelvis, septic bursitis, ischiorectal abscess, gluteal hematoma, gluteal tumor, and rheumatic bursitis.

The patient lies supine, and the clinician performs a passive unilateral straight leg raise. If a unilateral restriction is noted, the clinician flexes the knee and notes whether the hip flexion increases. If the restriction was caused by the lumbar spine or hamstrings, the hip flexion should increase. The sign of the buttock test is positive if the hip flexion does not increase when the knee is flexed. If the sign of the buttock is encountered, the patient must be immediately returned to his or her physician for further investigation.148

Posterior Pelvic Pain Provocation Test

The posterior pelvic pain provocation test, as described by Ostgaard and colleagues,149 is performed with the patient in supine. The clinician passively flexes the involved hip of the patient to 90 degrees and a posteriorly directed force is applied through the longitudinal axis of the femur (Fig. 29-25). The test is considered positive for SIJ dysfunction if the patient reports a deep pain in the gluteal region during the test.

Gaenslen's Test

The patient is positioned supine at the edge of the side of the bed with the painful leg resting very near to the end of the bed, and resting symptoms are assessed. The leg furthest from the edge of the bed (nontested leg) is flexed 90 degrees at the hip and held by the clinician using one hand. The clinician passively positions the upper leg (test leg) into hyperextension at the hip so that it hangs over the edge of the table (Fig. 29-26).150 The clinician applies a further stretch to the test leg into hip extension and adduction up to six times while a flexion-based counter force is applied to the flexed leg. Pain with this maneuver is considered a positive test for an SIJ lesion, pubic symphysis instability, hip pathology, or an L4 nerve root lesion. The test also stresses the femoral nerve. This test demonstrates poor diagnostic value secondary to poor to fair specificity.56 Overall, there is limited research pertaining to this test in order to make strong conclusions.

Yeoman's Test

This test151 is performed with the patient positioned prone. The clinician stabilizes the patient's sacrum with the palm of one hand. With the other hand, the clinician grasps the patient's distal thigh and extends the patient's hip (Fig. 29-27). At the end of the available motion, the hip is hyperextended so that the innominate is forced into anterior rotation. A positive test produces pain over the SIJ. Other structures that are stressed with this maneuver include the lumbar spine, the hip joint, and the iliopsoas muscle.

Thus far, the success of interventions at this joint has been mixed, due in part to the poor reliability with many of the examinations used. The success of any intervention depends on the quality and accuracy of the examination and the subsequent evaluation. It follows that if the examination gives an inaccurate diagnosis, the intervention may have a mixed result. It is reasonable to assume that the SIJ is a source of pain for one of the two reasons:152

1. There is some support for the notion of an inflammatory condition within the joint either causing or associated with the pain.153–155 Inflammatory processes such as those found in ankylosing spondylitis are known to affect the SIJ.

2. The joint is unstable through ligamentous laxity or tearing of the joint capsule.111,156,157

Given that the chosen intervention for the SIJ, like the spine, depends largely on the philosophy or background that he clinician uses to establish the diagnosis. There appears to be three major schools of thought152:

1. Those who regard the SIJ as either irrelevant or rarely an issue in clinical practice.

2. Those who consider the clinical examination of the SIJ as either useless or of minimal utility.

3. Those who regard structural and biomechanical aspects of the SIJ as the key determinants in the problem of back pain.

Although the philosophies may differ, the principles behind the interventions for SIJ impairments should remain constant:

• A joint that has reduced motion (hypomobility) requires mobilizing techniques, muscle release techniques, and exercises that are designed to restore normal optimal alignment and controlled mobility.
• A joint that demonstrates excessive motion (hypermobility and/or instability) requires techniques and exercises that are designed to stabilize or balance forces around the hypermobile or unstable joint.83 These include exercises to control joint motion and, on occasion, joint compression through the use of an external brace (SIJ belt).
• A joint that demonstrates signs and symptoms of excessive compression (due to intrinsic factors or extrinsic factors) requires techniques based on the cause of the compression. For example, joint compression caused by fibrosis benefits from the use of specific passive articular mobilization techniques whereas joint compression caused by over-activation of muscles benefits from techniques including muscle energy, trigger point therapy, and biofeedback.

The techniques and exercises used for the SIJ should always be based on the stage of healing and patient tolerance, and must take into account the influences that the lumbar spine and hip motions can have on this area.

Acute Phase

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

• decrease pain, inflammation, and muscle spasm;
• increase weight-bearing tolerance, where appropriate;
• promote healing of tissues through sufficient stabilization;
• increase pain-free range of SIJ motion and surrounding structures;
• regain soft tissue extensibility around the pelvic region;
• regain neuromuscular control;
• allow progression to the functional stage.

For the most part, exercises are avoided in the acute phase because they tend to increase the symptoms. Pain relief may be accomplished initially by the use of cryotherapy, and electrical stimulation (TENS), gentle muscle setting exercises. 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.158–160

Clinicians often correct leg length discrepancies of greater than 0.5 inches, as such inequalities have been described as altering normal SIJ function.161

SIJ and pelvic stabilization orthoses have been employed in an attempt to limit SIJ motion and improve proprioception (Fig. 29-28).161–164 These measures are particularly indicated when the joint has been demonstrated to be inflamed by the anterior or posterior stress tests. Not much force from these belts (20–50 N) is necessary to afford relief to the patient.162 The position of the belt in terms of its height on the ilium should be experimented with to find the optimal position for pain relief. The recommended position is just above the greater trochanter (Fig. 29-28). A bicycle inner tube can be used as a substitute SI belt, as this is the right width and has the correct degree of elasticity. The following conditions appear to respond well to bracing:

1. Sacroiliitis.

2. SI hypermobility/instability: (pre- and postpartum and microtraumatic).

3. Pubic instability (may afford some relief).

Once the pain and inflammation is under control, 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.

Aggressive manual therapy has a very limited place in the intervention of the acutely inflamed joint. In almost every case, the presence of a positive stress test contraindicates the use of passive mobilization or manipulation for that joint. However, mobilization or manipulation of the contralateral joint may reduce the stress on the painful and inflamed articulation. Gentle manual techniques such as myofascial release, grade I–II joint mobilizations, massage, gentle stretching, and muscle energy techniques should be attempted and continued if effective.

Functional Phase

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

• The severity of the injury.
• The healing capacity of the patient.
• How the condition was managed during the acute phase.
• The level of patient involvement in their rehabilitation program.

The goals of this phase are

• to significantly reduce or to completely resolve the patient's pain;
• to restore full and pain-free SIJ range of motion;
• to integrate the lower kinetic chains into the rehabilitation;
• complete restoration of normal gait, where appropriate;
• the restoration of pelvic and lower quadrant strength and neuromuscular control.

Intervention strategies should emphasize pelvic stabilization,124 the elimination of trunk/lumbar/hip and lower extremity muscle imbalances, and the correction of gait abnormalities.165 The exercises used in the lumbopelvic stabilization exercise progression are described in detail in Chapter 28. During this stage, the patient learns to initiate and execute functional activities without pain and while dynamically stabilizing the SIJ in an automatic manner. Muscle imbalances around this joint complex are common. The same principles apply here as elsewhere: stretch those muscles that are tight or adaptively shortened and strengthen those muscles that are found to be weak. The muscles to be stretched around this joint complex are based on the clinical findings but usually include the erector spinae, the quadratus lumborum, the rectus femoris, the iliopsoas, the tensor fascia lata, the hip adductors, and the deep external rotators of the hip, especially the piriformis, and the gluteus maximus.35,37 Postural correction and the correction of compensatory movements need to be addressed. Corrective exercises may be used to position the innominate bone in proper relation to the sacrum.

The focus of the therapeutic exercises for this region is to augment the force-closure mechanism and to reduce any stress that could prove detrimental to the SI complex. The exercises prescribed must challenge and enhance muscle performance while minimizing loading of the SIJ to reduce the risk of injury exacerbation. Inter-individual differences in injury status and/or training goals may allow for a continuum of required muscle stress and acceptable loading of the spine and SIJ.166 Stabilization exercises and joint positioning can help the patient 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.167

The strengthening component of the exercises is aimed at improving the function of the muscles of the inner and outer groups. The appropriate muscles must be isolated and then retrained to increase their strength and endurance, and to automatically recruit to support and protect the region.

A four-stage program has been designed to isolate and retrain the inner and outer muscle groups.73,168

Stage 1

• Levator ani. The patient is first taught the location of the levator ani in supine. To strengthen the muscle, the patient is asked to shorten the distance between the coccyx and the pubic symphysis and to hold the contraction for 10 seconds (Fig. 29-29). When the muscle contracts properly, the transverse abdominis muscle can be felt to contract at a point 2 cm medial and inferior to the ASIS, there is no contraction of the buttocks, and by carefully palpating the sacral apex, the sacrum is felt to counternutate slightly as the levator ani contracts. The exercise is repeated 10 times.
• Transversus abdominis/multifidus. The abdominal drawing-in maneuver is one exercise known to result in preferential activation of the internal oblique and TrA.72,169–171 To test for isolation of the TrA, the patient is positioned prone, and a pressure biofeedback unit is placed underneath the abdomen73,79 (Fig. 29-30). The cuff is inflated to a base level of 70 mm Hg. The patient is asked to draw the navel up and in toward the chest (abdominal hollowing). When the muscle contracts properly, an increase in tension can be felt at a point 2 cm medial and inferior to the ASIS. If a bulging is felt at this point, the internal oblique is contracting. The multifidus is palpated simultaneously and should be felt to swell at a point just lateral to the spinous process.

Stage 2

The stabilization program is progressed to the next stage with the introduction of lower or upper extremity motion, which changes the focus of the program from the inner muscle group to the outer muscle group.

In the supine position with the hips and the knees flexed, the patient is asked to isolate the inner muscle group, while maintaining the lumbar spine in a neutral position. From this position, the patient is asked to slowly let the knee fall to one side (Fig. 29-31). Alternatively, the patient may extend the leg with the foot supported on the table.

The next step in the progression involves asking the patient to slowly extend this leg while maintaining the hip and the knee flexed (with the foot lifted) without touching the table (Fig. 29-32). This exercise initially is performed unilaterally and then is progressed to alternate leg extensions. The same exercises may be performed sitting on a gym ball or lying supine on a long roll. By making the base unstable, the exercise becomes more difficult without having to progress to the next stage.

Exercising on a gym ball requires core stability (inner muscle group control), coordination, and appropriate postural reflexes. While sitting on the ball, the patient is asked to contract the muscles of the inner muscle group. This contraction is maintained while the patient moves forward and backward, and up and down on the ball. The patient is instructed to incorporate the co-contraction of the inner muscle group into their activities of daily living.

If the individual muscles of the outer muscle group are weak or poorly recruited, the exercise program should include isolation and training at this time.

• Posterior oblique system. In the posterior oblique system, it is common to find the gluteus maximus both lengthened and weak.12 Having the patient squeeze the buttocks together and sustain the contraction for 10 seconds isolates the gluteus maximus. A surface electromyography unit can provide a useful biofeedback system for this muscle. The exercise is progressed by having the patient lie prone over a gym ball and asking him or her initially to recruit the inner muscle group and then to extend the hip while the knee is flexed. Lifting the extended thigh increases the degree of difficulty. Leg extension machines can help to strengthen the gluteus maximus. Initially, the patient exercises in the supine position with one or both feet on the foot plate. Functional training is introduced by having the patient practice going from sitting to standing with a stabilized trunk, using primarily the gluteus maximus muscle.
• Lateral system. In the lateral system, the posterior fibers of the gluteus medius are often weak, which can have a marked effect on walking and load transference through the hip joint.91 Isolation of the gluteus medius is taught in the side lying position with a pillow placed between the knees. The exercise is progressed by asking the patient to lift the knee off the pillow and then to extend the knee while maintaining the correct position of the trunk and the hip. Resistance can be added using elastic tubing or a cuff weight.
• Anterior oblique system. Isolation of the anterior oblique system involves training the specific contraction of the external and internal oblique abdominals. When the external obliques contract bilaterally, the infrasternal angle narrows, whereas when the internal obliques contract bilaterally, the infrasternal angle widens. The patient is taught to palpate the lateral costal margin and to specifically widen and narrow the infrasternal angle through specific contraction of the oblique abdominals.

The progression includes activation of the anterior and posterior oblique systems and differentiation of trunk from thigh motion. To begin, the patient is supine with the hips and the knees flexed, both feet on the bed. The patient is instructed to bridge and then to rotate the trunk and the pelvic girdle at the hip joints in the unsupported position, while maintaining the lumbar joints in a neutral position.

Stage 3

Stage 3 exercises involve controlled motion of the “unstable region.”73 Because this stage is much more advanced, it is used only when required by an individual's work or sport. The protocol includes concentric and eccentric work with variable resistance in all three planes.

Stage 4

73 Stage 4 of the protocol involves stabilization during high-speed motions. Very few people require stage 4 stabilization, particularly in view of the fact that high-speed exercise tends to reduce the stabilizing capability of the trunk muscles.79

In addition to the exercise program, the patient should be educated on the trunk and the lower extremity positions to avoid (those that produce an excessive or sustained sacral counternutation or a decrease in lumbar lordosis) and those to adopt (the positions that enhance sacral nutation and enhance the lumbar lordosis). For example, the patient should be advised to maintain an anterior pelvic tilt during sitting, either actively or passively with the use of a lumbar roll.

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

As symptoms are controlled, therapy should be advanced to activity-specific stabilization exercises to facilitate return to function at the patient's occupation, sport, or avocational activities.

Integration of Practice Patterns 4D and 4E: Impaired Joint Mobility, Motor Function, Muscle Performance, Range of Motion Associated with Connective Tissue Dysfunction, and Localized Inflammation

Spondyloarthropathies

The spondyloarthropathies are a group of inflammatory arthritic conditions that share certain clinical and laboratory features (see Chap. 5).172

• An inflammatory arthritis, which manifests with pain associated with stiffness.
• The absence of a rheumatoid factor; hence the distinction of the group as “seronegative” spondyloarthropathies.
• The tendency for the arthritis to be asymmetric and involve the lower extremities.
• Often, inflammation at the insertion of tendons into bone (enthesitis), accompanied by certain extra-articular features, including skin and mucous membrane impairments, bowel complaints, eye involvement, and aortic root dilation.
• The familial aggregation, which occurs within each condition and among the entities within the group.
• An association with HLA-B27, documented in the diseases included in this group.

Ankylosing Spondylitis

Ankylosing spondylitis (Bekhterev's or Marie-Strümpell disease) is a chronic rheumatoid disorder that is usually progressive, resulting in a full ankylosing of the SIJs.172 Men generally have the more severe form affecting the spine, whereas in women, the peripheral joints are more often affected.

The typical radiographic changes are seen primarily in the axial skeleton, especially in the SI, intervertebral, zygapophyseal, costovertebral, and costotransverse joints.173 In addition, ankylosing spondylitis is one of the most common rheumatic disorders associated with radiologic abnormalities of the pubic symphysis, with pubic synchondrosis present in 20–25% of the patients.174 In fact, changes of the symphysis can sometimes precede spine involvement.174

Tests to discriminate SIJ tenderness caused by ankylosing spondylitis from that caused by mechanical spine conditions have traditionally included passive hip extension, A-P pressure applied to the sacrum, and the primary stress tests. However, these tests have been found to be poorly reproducible and inaccurate in making any distinction.99

Although radiologic evidence of sacroiliitis is accepted as being obligatory for the diagnosis of ankylosing spondylitis, the clinical signs (see Chap. 5) may predate radiologic abnormalities by months or even years.172

Groin Pain

Chronic pain in the groin region (see Chap. 19) is a difficult clinical problem to evaluate, and in many cases, the cause of the pain is poorly understood. The differential diagnosis of groin pain and tenderness includes adductor muscle strain, prostatitis, orchitis, inguinal hernia, urolithiasis, ankylosing spondylitis, Reiter's syndrome, hyperparathyroidism, metastasis, osteitis pubis, stress fracture, rheumatoid arthritis, tendonitis, degenerative joint disease of the hip, bursitis, stress fracture, conjoint tendon strains, inguinal ligament enthesopathy, and entrapment of the lateral cutaneous nerve of the thigh.175–177

Other nerve entrapment syndromes have been described as a possible cause of adductor region pain, with the anterior division of the obturator nerve in the thigh,178 the ilioinguinal nerve, and the genitofemoral nerve having all been inculpated.179

Osteitis Pubis

Many theories have been put forward concerning the etiology and progression of this disease, but the cause of osteitis pubis remains unclear.

Osteitis pubis is seen in athletes who participate in activities that create continual shearing forces at the pubic symphysis, as with unilateral leg support or acceleration–deceleration forces required during multidirectional activities. These include activities such as running, racewalking, gymnastics, soccer, basketball, rugby, and tennis. Pain with walking can be in one or several of many distributions: perineal, testicular, suprapubic, inguinal, and in the scrotum and perineum.180 Overuse is the most likely etiology of the inflammation, and the process is usually self-limiting.180

Osteitis pubis has been likened to gracilis syndrome, an avulsion fatigue fracture involving the bony origin of the gracilis muscle at the pubic symphysis and occurring in relation to the directional pull of the gracilis.181 However, osteitis pubis does not necessarily involve a fracture. The process could be the result of stress reaction, which might be associated with several biomechanical abnormalities.

Osteitis pubis usually appears during the third and fourth decades of life, occurring more commonly in men.182 The pain or discomfort can be located in the pubic area, one or both groins, and the lower rectus abdominis muscle. Symptoms of osteitis pubis have been described as “groin burning,” with discomfort while climbing stairs, coughing, or sneezing.

During the physical examination, pain can be elicited by having the patient squeeze a fist between the knees with resisted long and flexed adductor contraction. Range of motion in one or both hips may be decreased. An adductor muscle spasm might occur with limited abduction and a positive FABER test.183,184 A soft tissue mass with calcification, and an audible or palpable click over the symphysis might be detected during daily activities.180

Correct examination of this region involves examining the position of the pelvic girdle. The normal position for the pelvic bowl is 45 degrees in the sagittal plane and 45 degrees in the coronal plane. Pubic motion is assessed by locating the pubic crest and then gently testing the mobility of each available direction.

Dysfunction of this articulation may be primary or secondary and, when present, is always treated first, because a loss of function or integrity of this joint disrupts the mechanics of the entire pelvic complex. The impairment pattern is determined by palpating the position of the pubic tubercles and correlating the findings with the side of the positive kinetic test, with the restricted side indicating the side of the impairment.

An altered positional relationship within the pelvic girdle is significant only if a mobility restriction of the SIJ or pubic symphysis, or both, is found. The inguinal ligament is usually very tender to palpation on the side of the impairment. It is common to find the pubic symphysis held in one of the four following positions:

1. Anteroinferior

2. Posterosuperior

3. Anterosuperior

4. Posteroinferior

These articular dysfunctions are treated using manual techniques (see “Therapeutic Techniques”).

Intervention for the inflammatory type of osteitis pubis is conservative and most athletes return to their respective sports within a few days to weeks.185 The intervention includes plenty of rest from weight-bearing activities, a course of nonsteroidal anti-inflammatory medicine, and physical therapy to gently mobilize, stretch, and strengthen the muscles about the groin.186 Patients should be able to swim for exercise.

An intervention protocol for osteitis pubis is outlined in Box 29-1.

Symphysis Pubic Dysfunction

Symphysis pubic dysfunction (SPD) describes the situation where the ligaments between the pubic symphysis become stretched and allow the bones to move with respect to each other (see Chap. 30). In severe cases, rupture of the symphysis may occur. This more severe form is called diastasis symphysis pubis (DSP). SPD commonly occurs during pregnancy, and should always be considered when examining patients in the postpartum period who are experiencing suprapubic, SI, or thigh pain. The associated ligamentous laxity during pregnancy is in response to the hormones progesterone and relaxin. Causes unrelated to pregnancy include the possibility of a structural misalignment of the pelvis. This pelvic misalignment results in increased pressure on the pubic symphysis cartilage, with subsequent pain.

The symptoms of SPD and DSP vary from person to person (see Chap. 30). Radiological evaluation may occasionally be useful in confirming the diagnosis.187 Therefore, the intervention is based on the severity of symptoms rather than the degree of separation as measured by imaging studies.187 Palpation reveals anterior pubic symphyseal tenderness. Occasional clicking can be felt or heard. The findings on the physical examination include positive SIJ stress tests (compression, distraction, and FABER tests). The range of hip movements will be limited by pain, and there is an inability to stand on one leg. Characteristic pain can often be evoked by bilateral pressure on the trochanters or by hip flexion with the legs in extension. However, such maneuvers may result in severe pain or muscle spasm and are not necessary for diagnosis.

In cases of DSP, there is likely an associated anteroposterior (A-P) compression (common) or a vertical shear (rare) fracture. Three types of DSP are described, indicating the severity of the injury188:

• Type 1 involves minor anterior damage, mild (less than 2.5 cm) pubic symphysis diastasis, and/or (vertical) pubic rami fractures.
• Type II has wide diastasis of the symphysis pubis, disruption of the anterior SI ligament complex, and (hinging) of the iliac bone on the sacrum at the intact posterior SIJ.
• Type III designates total disruption of the SIJ, a diastasis of greater than 2.5 cm has been shown to indicate disruption of the anterior SIJ at least, but it is frequently associated with total SIJ disruption.

Although the symptoms can be dramatically severe in presentation for SPD and DSP, a conservative management approach is often effective (see Chap. 30).187

Resolution of symptoms in approximately 6–8 weeks with no lasting sequela is the most common outcome in SDP and DSP.187 Occasionally, patients report residual pain requiring several months of physical therapy but long-term impairment is unusual. Surgical intervention is rarely required but may be used in cases of inadequate reduction, recurrent diastasis, or persistent symptoms.

Peripartum Posterior Pelvic Pain

More than 50% of women experience peripartum posterior pelvic pain (PPPP) or low back pain (LBP) during pregnancy with one-third of these women experiencing severe pain (see Chap. 30).189–191,192

Hall and colleagues,189 in a two-case report provided preliminary evidence suggesting that a combination of manual therapy (muscle energy techniques directed at identified pelvic and sacral positional faults) and therapeutic exercise (neuromuscular reeducation of the transverse abdominis and multifidus with isometric hip adduction and abduction in a semireclined position, and standing exercises to strengthen the posterior oblique system [gluteus maximus and contralateral latissimus dorsi]) may be an effective intervention for peripartum patients reporting posterior pelvic pain.189

Coccydynia

Coccygeal pain is relatively common. The coccyx can move anteriorly or posteriorly. There are a number of ligaments around this area which can be injured:

• Anterior (ventral).
  • Lateral sacrococcygeal.
  • Anterior (ventral) ligament of the coccyx (caudal extension of the anterior longitudinal ligament).
• Posterior (dorsal).
  • Superficial posterior (dorsal) sacrococcygeal (caudal extension of the ligamentum flavum).
  • Deep posterior (dorsal) sacrococcygeal (caudal extension of the posterior longitudinal ligament).
  • Intercornual ligament.

The dominant muscle in this area is the levator ani, which has connections with the

• iliococcygeal ligament;
• pubococcygeal ligament.

Coccydynia tends to occur when the coccyx becomes stuck into flexion with an accompanying deviation. The causes can be muscle scarring or trauma.

Correction of this impairment involves grasping the coccyx after inserting the index finger in the anal canal. The coccyx is distracted and pulled posteriorly, while pulling laterally on the medial surface of the ischial tuberosity.

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

Sacral Stress Fracture

Repetitive loading on the body can lead to the development of stress fractures. Stress fractures have been described as a cause of back pain, especially fractures of the pelvis and pars interarticularis of the sacrum.193 Back and buttock pain caused by sacral stress fractures are less common but may occur in athletes and in the elderly.194 Fractures in the latter group have been reported both with and without trauma.

The cause of sacral stress fractures is controversial. These fractures are believed to result from stress concentrations of vertical body forces, which are dissipated from the spine to the sacrum and the sacral alae and then onto the iliac wings.195 In addition to abnormal stresses on normal bone, normal stress on abnormal bone can produce these fractures, especially in the elderly. Patients who sustain such insufficiency fractures may have predisposing factors, including idiopathic osteoporosis, irradiation-induced osteoporosis, steroid-induced osteoporosis, or osteoporosis associated with malignancy.193 Another cause cited for sacral fractures is progressive insufficiency of the supporting muscles.196 These fatigue fractures may result from the transfer of loading forces directly to the bone, without absorption of some energy by the muscles. Other reported causes of sacral stress fractures are differences in physical demands, environmental and genetic influences, training methods, footwear, and intensity of training.196 Atwell and Jackson197 suggested that leg length inequality may increase the stress on one side of the sacrum, but this has not been proven by biomechanical analysis.193

Patients with sacral stress fractures typically present with low back pain and sacral pain that may radiate into the buttocks. However, pain may be referred to the groin and, occasionally, down the leg.197 In the case of an athlete, the history may reveal a recent history of stress fracture in the same area, or a rapid increase in training intensity prior to the onset of symptoms.126 Insufficiency fractures of the sacrum in nonathletes have been reported to mimic disk disease, spinal stenosis, and tumors.198 Irritation of the cauda equina or the sacral nerve roots may explain the wide variety of symptoms seen in patients with sacral stress fractures.193,199

Physical examination may not provide reliable signs initially, because many of these patients have diffuse low back, sacral, and buttock pain. However, most patients will have localized tenderness over the sacrum and SIJ.193–195,197–199 Tenderness in the upper gluteal areas tends to be coexistent with sacral stress fractures, and tenderness in this region may contribute to the impression that the origin of the pain is centered in the more proximal lumbar spine.193 Most patients are neurologically intact, with no signs of nerve root irritation. The Patrick's, or the FABER (flexion, abduction, external rotation) test may or may not be positive, so it cannot be depended on in making a diagnosis.193

The most sensitive method of evaluating the sacrum for occult stress fractures and other bone lesions is a bone scan using three-phase scintigraphy.200 This bone imaging technique can help detect stress fractures as early as several days after the fracture occurs. In contrast, plain radiographs of the lumbosacral spine and the pelvis, although useful to rule out other causes of back pain, are not helpful in diagnosing sacral stress fractures.194

Patients with sacral stress fractures recover quickly with rest. Most patients are able to return to their normal activity levels in 4–6 weeks with no long-term sequelae.193 Anti-inflammatory agents and analgesics may be used as adjunctive treatment for patient comfort. Cycling or running in a pool may be used until weight-bearing activities are tolerated.

Normally, pelvic impairments are presented as isolated entities when, in fact, clinically, they tend to occur in combination. It is essential that the impairments, functional limitations, and disability found during the examination guide the intervention.

To Restore Posterior Rotation of the Right Innominate

The patient is in the prone lying position, with the right hip and the leg over the edge of the table. The clinician stands at the patient's right side. The patient's right foot is placed between the clinician's legs and held there. While monitoring the sacral sulcus with the index finger of the left hand, the clinician moves the patient's right leg to the barrier (Fig. 29-33). The patient is asked to gently push the right foot toward the foot of the table. This movement is resisted by the clinician's legs, and after 3–5 seconds, the patient is told to relax. Once again, when full relaxation has occurred, the slack is taken up, and the patient's right leg is moved in the direction of hip flexion until the monitoring finger indicates the new barrier has been reached. This mobilization is repeated three times and followed by a reexamination.

To Restore Anterior Rotation of the Left Innominate

The patient is in the prone lying position, with the clinician standing on the patient's side. With the left hand, the clinician supports the anterior aspect of the patient's left thigh, at a point just above the knee. The clinician places the heel of his or her right hand over the patient's left posterior inferior iliac spine. Extending the left hip until motion at the lumbosacral junction is perceived (Fig. 29-34), the clinician localizes the motion barrier. The patient is instructed to flex the left hip against the clinician's resistance. This isometric contraction is held up to 5 seconds, following which the patient is instructed to completely relax. The new barrier to anterior rotation is achieved by further extension of the hip. The mobilization is repeated three times and followed by a reexamination of function.

History

A 47-year-old man presented at the clinic, with left-sided low back and buttock pain that had developed while he was at work 2 weeks previously. When describing the mechanism of injury, the patient reported feeling something “pop” in his low back during a lifting maneuver that involved bending forward and twisting to the right. The pain was now localized to an area slightly inferior to the left posterosuperior iliac spine, which he reported as being very tender to the touch. The pain was aggravated with forward bending and turning at the waist to the left in the sitting position. The patient reported sleeping well, if he remained prone, and there were no complaints of paresthesias or anesthesias. The patient denied any neurologic symptoms related to cauda equina or spinal cord involvement. He was in otherwise good health.

Questions

• 1. Given a distinct mechanism of injury, what type of structure(s) could be at fault with complaints of left-sided low back and buttock pain?

• 2. What does the region of localized tenderness tell the clinician?

• 3. Why do you think the patient is sleeping well in the prone position?

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

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

History

A 44-year-old man came to the clinic complaining of worsening abdominal and midline pelvic pain. The pain had developed gradually, and there was no report of recent direct trauma or acute injury. The pain was aggravated with forced flexion at the waist and the Valsalva maneuver, but the patient reported no pain at rest. The pain, described as a sharp, “stabbing” sensation, remained fairly localized to his upper pelvis and lower abdominal area.

The patient had no history of abdominal or genitourinary diseases or surgeries, and he had not experienced similar symptoms in the past. A review of systems was unremarkable. He denied dysuria, hematuria, diarrhea, constipation, fever, chills, or weight change.185

The patient frequently participated in physical activity and played soccer, averaging four games per week, an increase from his usual level of commitment. An inguinal hernia had been ruled out by his physician.

Questions

• 1. What structure(s) could be at fault when abdominal and midline pelvic pain is the major complaint?

• 2. What is the significance of the Valsalva maneuver?

• 3. Why are the questions with regard to dysuria, hematuria, diarrhea, constipation, fever, chills, or weight change pertinent?

• 4. What does no pain at rest suggest?

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

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

• 1. Which SIJ ligament forms the major connection between the sacrum and the innominate, filling the irregular space posterosuperior to the joint between the lateral sacral crest and the iliac tuberosity?

• 2. Which sacral motion places tension on the posterior (dorsal) SI ligament of the SIJ?

• 3. What are the muscle actions of the piriformis muscle?

• 4. Which muscle group comprises the pelvic floor muscle group?

• 5. During right side bending, which sacral and right innominate motions are purported to occur?

Answers