Sonographic appearances of the normal ulnar nerve in the cubital tunnel

Abstract

There were differences in the CSA of the ulnar nerve between some age groups, but there was no variation with sex or handedness. Sonography can evaluate the morphologic changes of the nerve during flexion of the elbow.

Clinical Assessment of the Ulnar Nerve at the Elbow: Reliability of Instability Testing and the Association of Hypermobility with Clinical Symptoms

“…However, the relatively higher frequency of perching relative to dislocation is consistent with prior reports in the literature 2,4,5,14 . We suspect that our investigational methods may have contributed to our findings.…”

“…The nerves that dislocate on physical examination are treated primarily with ulnar nerve transposition or epicondylectomy. If we had excluded perchable nerves from our subject group, the overall prevalence of hypermobility was 26% and the data would more closely correlate with those of Ozturk et al, who documented subluxation in 23% and dislocation in 8.5% of 212 elbows 14 . The high degree of bilateral hypermobility that was noted supports a similar finding by Ashenhurst 5 .…”

Sonographic incidence of ulnar nerve (sub)luxation and its associated clinical and electrodiagnostic characteristics

“…There are 3 earlier dynamic ultrasound studies about (sub)luxation during elbow flexion in healthy controls. 5,8,9 One study showed subluxation in 53 of 200 elbows (27%) and luxation in 39 elbows (20%). 8 Another study of 212 elbows found subluxation in 49 (23.1%) and luxation in 18 elbows (8.5%).…”

“…8 Another study of 212 elbows found subluxation in 49 (23.1%) and luxation in 18 elbows (8.5%). 9 The third study revealed ulnar nerve displacement in 24.3% of 78 elbows from 39 healthy subjects; 20.5% (16/78) had subluxation, and 3.8% (3/78) had luxation. 5 These earlier reported incidences in healthy subjects are much higher than in our study (5.7% for both luxation and subluxation).…”

“…It moves anteriorly and flattens during flexion of the elbow, and this flattening is most marked with (sub)luxation. 8,9,12 Also, during elbow flexion the nerve is stretched, because it courses behind the axis of rotation. Okamoto et al suggested that (sub)luxation produces additional frictional forces and increased compression against the hard convex floor of the tip of the epicondyle, leading to chronic inflammation and a larger CSA.…”