Ulnar Neuropathy at the Elbow

Abstract

Ulnar neuropathy at the elbow (UNE) is the second most commonly encountered entrapment neuropathy after carpal tunnel syndrome. The term “cubital tunnel” syndrome is sometimes used to refer to UNE, but this is misleading as the term accurately describes only compression of the ulnar nerve as it passes beneath the aponeurotic arch of the flexor carpi ulnaris muscle (FCU). Because the ulnar nerve may also be compressed in the ulnar (condylar or retrocondylar) groove behind the medial epicondyle, the term UNE is more encompassing of the range of pathophysiological processes that may lead to ulnar nerve injury in the vicinity of the elbow. Compressive lesions of the ulnar nerve as it passes across the elbow may selectively affect some nerve fascicles more than others, which may cause some difficulty in localizing an ulnar nerve lesion to the elbow. What then are the typical clinical features of ulnar neuropathy at the elbow and how accurate are the various electrophysiologic tests for the diagnosis of UNE? What is the natural history of UNE if left untreated and how do conservative and surgical measures impact this prognosis? These and other questions are the subject of this chapter.