Proximal and distal motor nerve conduction in obturator and femoral nerves

Objective: To study the proximal and distal motor conduction properties of obturator and femoral nerves. Design: For evaluation of distal motor conduction properties, obturator and femoral nerves were stimulated at the inguinal ligament, and M responses w ere recorded with needle electrodes from gracilis and rectus femoris muscle s. Upper lumbar roots were stimulated with needle electrodes inserted betwe en L1-L2 vertebral laminae. Participants: Sixteen healthy adults, eight of each gender, age 22 to 52 ye ars (mean 37.5). Main Outcome Measures: Description of a method for assessing motor conducti on along the obturator nerve and evaluating proximal motor conduction measu rements obtained with stimulation of obturator and femoral nerves. Results: Distal motor conduction latencies were 3.9 +/- 0.7msec for gracili s and 4.6 +/- 0.5msec for rectus femoris after stimulation of obturator and femoral nerves, respectively. Proximal conduction times from lumbar verteb ral level were 10.4 +/- 0.3msec for the obturator nerve and 10.8 +/- 0.4mse c for the femoral nerve. Conduction velocities of proximal segments of both nerves were similar, 62m/sec for the obturator nerve and 65m/sec for the f emoral nerve. Submaximal stimulation of both nerves evoked H-reflex respons es from their associated muscles. Conclusions: Motor conduction properties of the obturator nerve can be asse ssed by the method described, particularly to differentiate between periphe ral, plexus, or radicular lesions that involve the obturator nerve.