Thanks to Dr. Brooke for presenting a case of shoulder pain with C6/C7 weakness and lack of sensation to the thumb which prompted the dreaded review of the brachial plexus, nerve roots and dermatomes.
The most commonly affected nerve root is C7 (~70%) followed by C6 (~20%). Sometimes it may not be clear that the problem is at the nerve root itself. Occasionally one can be tricked to by peripheral neuropathies mimicking nerve root compression. Below are a few distinguishing factors.
Provocative maneuvers are also helpful tools to distinguish the location of the lesion and to assess other etiologies on the differential.
- Spurling test: highly specific and sensitive for cervical radiculopathy; passive movement of patient's next into lateral flexion and extension followed by gentle downward axial compression, + test reproduces radicular symptoms
- Shoulder abduction test: highly specific; place the palm of the affected side on the patient's head; + test results in relief of radicular symptoms
- Upper limb tension test: most sensitive to rule out radiculopathy; with the patient supine and the shoulder neutral and the elbow and wrist flexed, the shoulder is then abducted 90 degrees and the elbow and fingers extended with wrist supination as the patient's neck moves to the contralateral side; + test reproduces radicular symptoms
- Tinel sign: low sensitivity, moderate specificity for carpal tunnel syndrome; pain or parasthesias in a median nerve distribution with tapping the volar wrist over the carpal ligament
- Phalen maneuver: moderate sensitivity and specificity for carpal tunnel syndrome; pain or parasthesias in the a median nerve distribution after 60 seconds of wrist flexion at 90 degrees with full elbow extension (for Carpal Tunnel review, see the associated AAFP article).
- Adson's test: for thoracic outlet obstruction; with inspiration, chin elevation and head rotation to the affected side a + test alters or obliterates the radial pulse
For additional review of provocative c-spine testing, refer to the Pain Physician article from 2003.