Effects of Different Elbow Positions on Latency and Amplitude of Motor Nerve Conduction Study of Ulnar Nerve

Ulnar nerve is formed by the branches of Medial cord of the brachial plexus and is one of the main nerves of upper limb. Ulnar nerve passes posterior to medial epicondyle of humerus so may be stretched or compressed in elbow movement.

To assess the ability of ulnar nerve motor fibers to pass stimulus in three different position of elbow joint (0°, 90°, 120° of elbow flexion).

The cross-sectional observational study was conducted on 30 normal healthy individuals (aged between 18 to 25 years) in Government Spine Institute, Civil Hospital, Ahmedabad. Subjects exposed to factors affecting nerve conduction velocities e.g. smokers, alcoholic, diabetic etc. were not included in the study. Subjects were selected by random sampling technique. Subjects were given supine lying position to measure latency (from artifact to first negative deflection) and amplitude (peak to peak) of right ulnar nerve from above and below elbow in three different positions of elbow (0°, 90°, 120° of flexion) using EMG instrument (RMS EMG EP MK-II, Version 1.1), measuretape, thermometer, weighing-machine, height-scale, universal-goniometer, sketchpen, spirit, pen, electrode gel, cotton and micropore adhesivetape.

Statistical analysis was done with ANNOVA test. F values for below elbow latency, above elbow latency, below elbow amplitude, above elbow amplitude are 0.0699, 0.1534, 0.1488, and 0.2336 respectively. Results showed insignificant difference at 0.05significance level in latency and amplitude of ulnar nerve in three different positions of elbow.

Study concludes that there is no effect of elbow positions on latency and amplitude during ulnar motor nerve conduction.