PATTERNS OF PAIN INDUCED BY DISTENDING THE THORACIC ZYGAPOPHYSEAL JOINTS

Background and Objectives. The study was designed to investigate the p atterns of referral pain associated with the thoracic zygapophyseal jo ints (C7-T1 to T2-3, T11-12). Methods. In 15 patients who had back pai n suspected to be of zygapophyseal origin and for whom pain was reliev ed by injection of local anesthetic into the joints under fluoroscopic guidance, the zygapophyseal joints from C7-T1 to T2-3, T11-12 were di stended by injecting contrast medium. If injection reproduced typical pain in the patient, the patient was asked to describe the distributio n of pain, which was recorded on a body diagram. Results. A total of 2 1 joints were studied. Composite pain distribution maps for the thorac ic zygapophyseal joints from C7-T1 to T2-3 and for the T11-12 joint we re drawn. The distribution of referred pain was as follows: pain in th e suprascapular region was referred from C7-T1 and Th1-2; pain in the superior angle of the scapula from C7-T1 and T1-2; pain in the midscap ular region from C7-T1, T1-2, and Th2-3; and pain in the paravertebral region around the site of injection and the area over the iliac crest from T11-12. Conclusions. The referred pain distribution for joints C 7-T1 to Th2-3 showed significant overlap.