Anconeus Detail

musculus anconeus detail

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.

Nerve: Radial nerve — branch of the posterior interosseous… Blood Supply: Posterior interosseous artery Region: Upper Arm

Anatomical Data

Origin, Insertion & Supply

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

Biomechanics

Function & Actions

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

Clinical Relevance

Clinical Notes

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.

Palpation

Palpated at the posterolateral elbow triangle during resisted elbow extension.

Pathology

Common Injuries & Conditions

Anconeus Rotational Flap for Radial Head Coverage

Anconeus muscle transposition covering exposed bone and hardware after radial head excision, providing vascularised soft tissue in the posterolateral elbow.