Electrodiagnostic confirmation of long thoracic nerve palsy.

Long thoracic nerve latencies were measured in 25 normal subjects. The nerve was stimulated at Erb's point. Monopolar electrodes were used to record the motor evoked response from the serratus anterior muscle. The mean long thoracic nerve latency was 3.9 +/- 0.6 ms. Four athletes with unilateral, isolated long thoracic nerve palsies were compared with the control group and with the uninvolved extremities. Long thoracic nerve latency examinations may help confirm the presence of long thoracic nerve palsy and test proximal nerve conduction.