The axial rotation and simultaneous lateral flexion of the cervical spine is kinesiologically related to the movements of the upper thoracic spine. Five brachialgia patients were found to have a hypomobile first rib on the painful side in a cineradiographic study. The kinesiologic finding was the following: when the neutrally positioned cervical spine was first maximally rotated passively away from the painful side, the passive lateral flexion was restricted in this position. This can be due to the first thoracic transverse process bumping against the subluxated first rib. This test of cervicothoracic mobility is useful in the examination of the thoracic outlet function.