Short Segmental Motor Conduction Studies of Ulnar Nerve at the Elbow according to Different Elbow Angle

J Korean Assoc EMG Electrodiagn Med 2008;10(1):22-27.
Published online June 1, 2008.

Abstract

Objectives: The purpose of this study is to investigate the effect of elbow position on conduction velocitiesof short segments across the elbow and to obtain optimal elbow position for short segmental ulnarmotor conduction study.Methods: Short segmental motor conduction studies of ulnar nerve were performed in nondominantupper limbs of twenty-five healthy adults. For each upper limb, ulnar nerve was stimulated at 2 cm intervalsfrom 4 cm below to 6 cm above the medial epicondyle with elbow position in extension and 45。,90。, and 135。flexion.Results: Each short segment across the elbow showed statistically significant slowing of conductionvelocities compared to that of forearm segment with elbow position in extension and 45。flexion(p<0.05). Each short segment across the elbow didn’t show statistically significant slowing of conductionvelocities compared to that of forearm segment with elbow position in 90。and 135。flexion (p>0.05),except the segment between 2 cm below the medial epicondyle and medial epicondyle with elbow positionin 90。flexion (p<0.05). Differences of nerve conduction velocity between forearm segment and eachshort segment across the elbow were minimal with elbow position from 90。to 135。flexion.Conclusion: This study suggest that the degree of elbow flexion should be maintained 135。full flexionin short segmental ulnar nerve conduction study.

Key Words: Motor nerve conduction study, Ulnar nerve, Elbow