Reliable, technically not demanding, electrophysiological tests make it possible to diagnose ulnar entrapment neuropathy at the elbow. The ulnar nerve was stimulated supramaximally at the wrist, below and above the elbow, and in the upper arm, and the sensory nerve action potential (SNAP) and compound muscle action potential (CMAP) were recorded. Sensory and motor nerve conduction velocities (SNCVs, MNCVs) were calculated in each segment. In 12 of 64 symptomatic extremities of 44 patients with a presumptive diagnosis of ulnar neuropathy at the elbow MNCVs of all segments were within normal limits and only SNCV across the elbow was significantly slowed (p<0.001). In 25 extremities of the patients SNAP was not obtained. Evidence of denervation in the first dorsal interosseous and abductor digiti minimi muscles was detected in about 50% of hands tested. This percentage was higher in the hands with no SNAP than those with SNAPs. It would appear that measurement of SNCV across the elbow is a more sensitive parameter to detect abnormal conduction across the cubital tunnel in patients with ulnar neuropathy.
- cubital tunnel syndrome
- entrapment neuropathy
- ulnar nerve
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)