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 were recorded with needle electrodes from gracilis and rectus femoris muscles. Upper lumbar roots were stimulated with needle electrodes inserted between L1-L2 vertebral laminae.

Participants: Sixteen healthy adults, eight of each gender, age 22 to 52 years (mean 37.5).

Main Outcome Measures: Description of a method for assessing motor conduction along the obturator nerve and evaluating proximal motor conduction measurements obtained with stimulation of obturator and femoral nerves.

Results: Distal motor conduction latencies were 3.9 +/- 0.7 msec for gracilis and 4.6 +/- 0.5msec for rectus femoris after stimulation of obturator and femoral nerves, respectively. Proximal conduction times from lumbar vertebral level were 10.4 +/- 0.3msec for the obturator nerve and 10.8 +/- 0.4msec 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 femoral nerve. Submaximal stimulation of both nerves evoked H-reflex responses from their associated muscles.

Conclusions: Motor conduction properties of the obturator nerve can be assessed by the method described, particularly to differentiate between peripheral, plexus, or radicular lesions that involve the obturator nerve.