Rare causes of ulnar nerve compression in the epitrochlear groove.

The commonest causes of ulnar nerve compression in the epitrochlear groove have been widely reported in the literature. The author reports four rare causes, viz.: neurinoma of the ulnar nerve (one case), compression of the ulnar nerve due to an arthrogenic ganglion (two cases), ulnar neuritis due to articular gout (two cases), and compression of the ulnar nerve due to post-traumatic fibrosis in the epitrochlear groove (one case).