Innervation of the human costovertebral joint: implications for clinical back pain syndromes

The diagnosis of pain in the upper back, shoulder, chest, and arm is often made with considerable confusion and may be accompanied by needless expense and suffering by the patient. Despite the paucity of evidence concerning the tissues and mechanisms responsible for interscapular and atypical chest pain or "pseudo-angina," practitioners of manual therapy maintain that manipulation of the costovertebral elements and associated soft tissues may be helpful in the treatment of these painful conditions.

We have examined the costovertebral complex in humans with respect to the presence of immune-like reactivity to neurofilament protein and the neuropeptide substance P and calcitonin gene-related peptide, markers that reveal the presence of axons in peripheral tissues.

Human costovertebral complexes obtained at autopsy were processed with standard histologic examination and immunocytochemical methods to detect the presence of neurofilaments, substance P, and calcitonin gene-related peptide.

Outcomes were descriptive and did not require statistical methods.

All costovertebral joints contained innervation within the anterior capsule and synovial tissues. In 4 separate cases, the costovertebral joints contained large intraarticular synovial inclusions or "meniscoids" found to contain small bundles of axons with immune-like reactivity to substance P. Axon bundles were identified in serial section with monoclonal antibodies to neurofilaments as well as with urea-silver nitrate staining.

The costovertebral joint has been considered a candidate for producing back pain and/or pseudo-angina that may be ameliorated by spinal manipulation. This study has demonstrated that the costovertebral joint has the requisite innervation for pain production in a similar manner to other joints of the spinal column.