Objectives: The current literature gives confusing advice on the position of the elbow in ulnar nerve conduction study. The purpose of this study was to determine the appropriate position of elbow flexion for a segmental ulnar nerve conduction study and to attain the basic information for an evaluation of ulnar neuropathy.

Methods
Segmental ulnar motor and sensory nerve conduction studies were performed bilaterally on 40 healthy korean adults(20 men and 20 women) with the age range from 19 to 56 years(mean age：29.86). The ulnar nerve was stimulated at 7 cm & 10 cm proximal to the active recording electrode respectively and 5 cm distal, and poximal to the medial epicondyle of the humerus for motor and sensory nerves at each elbow flexion position of 0^o, 45^o, 90^o, and 135^o. The segmental distances were measured in each position.

Results
The segmental nerve conduction velocity(NCV) of the elbow segment increased with the degree of elbow flexion, and it was faster than the forearm segment at 90^o and 135^o of elbow flexion. The NCV showed no statistical difference in each elbow position.

Conclusion
We conclude that the degree of elbow flexion should be maintained 90^o or above in an ulnar nerve conduction study.