The cervical rotation lateral flexion test (CRLF test), developed earlier, was used to examine patients with brachialgia and thoracic outlet syndrome (TOS) symptoms to detect possible restriction of the movement of the first rib. The test was performed for 23 patients, five of them both before and after treatment. The patients were assessed independently by two clinicians to analyze the interobserver reliability. A cineradiographic examination was performed so that any restriction of the movement of the first rib during expiration and inspiration could be detected objectively. The interobserver repeatability of the test was excellent, thus making the cineradiographic examination unnecessary. It is recommended that this test be included in the clinical investigation of all patients with brachialgia with or without radicular pain.