Movement of the ulnar nerve at the elbow: a sonographic study.

OBJECTIVES: The aim of this study was to measure the degree of movement of the ulnar nerve in the cubital tunnel using sonography in patients with ulnar neuropathy at the elbow compared to a healthy control group.

METHODS: We examined the ulnar nerve in the cubital tunnel using sonography with the elbow extended and then flexed in 26 patients with ulnar neuropathy and 13 control participants. The distance from the ulnar nerve to the skin, medial epicondyle, and tip of olecranon at the inlet of the cubital tunnel and the distance from the ulnar nerve to the skin and olecranon recess at the outlet of the cubital tunnel were measured when the elbow was extended and flexed, respectively. Displacement of the ulnar nerve during elbow extension and flexion between patients with ulnar neuropathy and controls was compared.

RESULTS: There was significantly greater displacement of the ulnar nerve to the medial epicondyle at the inlet of the cubital tunnel in the patients with ulnar neuropathy (mean ± SD, 4.22 ± 3.79 mm) compared to the controls (1.76 ± 1.51 mm) during elbow extension and flexion (P = .008).

CONCLUSIONS: A significantly greater degree of movement of the ulnar nerve occurs in patients with ulnar neuropathy at the elbow compared to healthy people, as determined by sonography.