The flexor carpi radialis H-reflex in lesions of the sixth and seventh cervical nerve roots.

In 143 normal subjects latencies of H-reflexes of the flexor carpi radialis muscle were well correlated with arm lengths. In 32 patients with injury to cervical roots C5 to C8 it was shown that latencies were only abnormal in lesions of roots C6 or C7. It is suggested that in most instances root C6 or C7 and, probably both roots in some cases are involved in the reflex pathway. Repeat electrophysiological examinations after surgery provided valuable data about the various types of nerve root recovery.