The anconeus is a small triangular muscle at the lateral elbow that assists triceps in elbow extension and, importantly, abducts the ulna during forearm pronation to maintain the ulnohumeral articulation. It is a key stabiliser of the posterolateral elbow.
| Origin | Posterior surface of the lateral epicondyle |
|---|---|
| Insertion | Lateral side of the olecranon and posterior surface of the ulna — proximal quarter |
| Nerve Supply | Radial nerve — branch of the posterior interosseous nerve (C7, C8) |
| Blood Supply | Posterior interosseous artery |
| Actions | Extends the elbow — assists triceps in the last degrees of extension; Abducts the ulna during pronation — stabilises the radioulnar joint; Tenses the posterior elbow capsule |
|---|
Anconeus is the muscle used as a rotational flap to cover the radial head in radial head excision or arthroplasty revision. In lateral elbow approaches (Kocher's approach), the internervous plane is between the anconeus (radial nerve) and extensor carpi ulnaris (PIN). Anconeus epitrochlearis (a variant muscle spanning the medial elbow) can compress the ulnar nerve.
Palpated at the posterolateral elbow triangle during resisted elbow extension.
Anconeus muscle transposition covering exposed bone and hardware after radial head excision, providing vascularised soft tissue in the posterolateral elbow.
