Case 16 - Supracondylar process: ligament of Struthers

Summary

Imaging description

Supracondylar process of the humerus is an osseous anatomic variation protruding on the anteromedial surface of the distal humerus 4 to 8 cm proximal from the medial epicondyle (Figure 16.1). The process extends inferiorly to the direction of the medial epicondyle. The process is usually about 1 cm long, but it may take the form of tubercle. Ligament of Struthers variably presents and extends from the apex of the supracondylar process to the medial epicondyle. These structures create a fibro-osseous tunnel, in which the median nerve (rarely ulnar nerve) and the brachial (or ulnar) vessels pass through.

Importance

Supracondylar process is found in 0.4–2.7% of Whites. The individuals with this anomaly are usually asymptomatic. However, symptoms have been reported with a fracture of the supracondylar process or entrapment of the nerve or vessel in the fibro-osseous tunnel. Associated anatomic variants include high division of the brachial artery, high origin of the anterior interosseous nerve branch, and high origin of the pronator teres. These anatomical variations need to be considered clinically as the presenting symptoms may vary and surgical treatment may need to be modified.

Typical clinical scenario

Supracondylar process is more prevalent in Whites than in Blacks, Native Americans, and Asians. It is more commonly found on the left and in males. There have been variable clinical presentations associated with supracondylar process in the sporadic case reports. Median nerve entrapment is most frequently seen and is designated as “supracondylar process syndrome,” associated with numbness and paresthesia of the radial and palmar skin. The symptoms are commonly related to or exacerbated by certain postures of the elbow and forearm. The supracondylar process may be palpable as a firm mass in its anatomical location. Following conservative treatment, resection of the process with the Struthers’ ligament and the periosteum may be indicated.