The ligament of Struthers is an inconstant fibrous band present in approximately 1-3% of individuals, connecting a supracondylar bony spur on the anteromedial humerus (approximately 5 cm above the medial epicondyle) to the medial epicondyle. It forms an accessory bony tunnel through which the median nerve and brachial artery pass, creating a potential entrapment site for the median nerve (pronator teres syndrome variant).
No normal anatomical function; represents a vestigial structure (homologous to the third condyle of other mammalian species). When present, it creates an accessory tunnel that can compress the median nerve.
A supracondylar spur and the ligament of Struthers are identified on lateral humerus radiograph as a bony excrescence approximately 5 cm above the medial epicondyle. Compression of the median nerve here produces proximal forearm pain with flexion, weakness of all median-innervated muscles including the pronator teres (distinguishing from more distal entrapment), and positive Tinel sign over the supracondylar process. Treatment requires division of the ligament and excision of the supracondylar spur.
The ligament of Struthers compressing the median nerve just above the elbow produces aching proximal forearm pain, positive Tinel over the supracondylar spur, and weakness of all median muscles including the pronator teres itself; X-ray identifies the supracondylar spur, and surgical treatment divides the ligament and removes the spur.
