In the thoracic spine, protection and function of the thoracic viscera take precedence over segmental spinal mobility. Although a significant source of local and referred symptoms, differential diagnosis of the thoracic region can be difficult. This is due to the complicated biomechanics and function of the region, the proximity to vital organs, and the many articulations.
The thoracic spine forms a kyphotic curve between the lordotic curves of the cervical and lumbar spines. The curve begins at T1–2 and extends down to T12, with the T6–7 disk space as the apex.1
The thoracic kyphosis is a structural curve that is present from birth.2 Unlike the lumbar and cervical regions, which derive their curves from the corresponding differences in intervertebral disk heights, the thoracic curve is maintained by the wedge-shaped vertebral bodies, which are about 2 mm higher posteriorly than anteriorly.
At the thoracolumbar junction, typically located between T11 and L1, the changes in curvature from one of kyphosis to one of lordosis vary quite widely according to posture, age, and previous compression fractures and resulting deformity.3,4
The cervicothoracic junction anatomically comprises the C7–T1 segment and functionally includes the seventh cervical vertebra, the first two thoracic vertebrae, the first and second ribs, and the manubrium.
Pain arising from the thoracic spinal joints has considerable overlap and can refer symptoms to distal regions (groin, pubis, and lower abdominal wall).
Apart from musculoskeletal lesions, the thoracic spine is also a common source of systemic pain, and the phenomenon of referred pain poses more diagnostic difficulties in the thoracic spine than in any other region of the vertebral column (Figure 12-1).5
Medical causes of thoracic pain.
The algorithm outlined in Figure 12-2 can serve as a guide to the examination of the thoracic spine and ribs (Figure 12-2).
Algorithm for examination of thoracic spine and ribs.
The history should include the chief complaints and a pain drawing. Determining the location of the pain can provide some clues as to the cause, as many of the thoracic structures are superficial. It is common for a patient with thoracic symptoms to have stiffness in the morning. However, sharp pain and stiffness that persist for greater than 30 minutes may indicate inflammation.
Morning stiffness is a moderately sensitive and specific finding (0.64 and 0.59, respectively) for ankylosing spondylitis.6