The Struthers’ ligament and the arcade of Struthers are two anatomical structures that are often confused. The Struthers’ ligament was described by anatomist John Struthers in 1854; it is a fibrous band that extends from a bone spur located on the anteromedial surface of the lower third of the humerus, known as the supracondylar process, and is inserted in the medial humeral epicondyle. The Struthers’ ligament passes over the median nerve and the brachial artery, which may cause compression of these structures. It may be observed even in the absence of the supracondylar process; even when present, it may not cause the compression of these structures.

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In contrast, the arcade of Struthers was first described in 1973 by Kane et al. It is sometimes defined as a thickening of the brachial fascia, and sometimes as an aponeurotic or musculoaponeurotic structure extending from the medial intermuscular septa to the medial head of the triceps brachii muscle at a variable distance above the medial humeral epicondyle.

The arcade of Struthers can cause compression of the ulnar nerve. Controversy exists in the literature regarding the existence of the arcade of Struthers. Some anatomical studies have found an anatomical formation consistent with the arcade of Struthers. Conversely, other studies have reported that the arcade of Struthers does not exist; rather, that there are only anatomical variations of the intermuscular septum and the forearm fascia.