Brachialis Distal Tendon

tendo distalis musculi brachialis

The brachialis inserts via a short broad tendon onto the coronoid process and the tuberosity of the ulna (ulnar tuberosity), just distal to the coronoid. It is the deeper of the two elbow flexors (beneath the biceps brachii) and provides approximately 50-60% of elbow flexion force. Unlike the biceps (which also supinates), the brachialis is a pure elbow flexor regardless of forearm rotation position.

Region: Forearm

Clinical Relevance

Clinical Notes

Distal brachialis avulsion is rare but occurs from a sudden eccentric load during elbow flexion (catching a heavy object, resisting a fall). It presents as anterior elbow pain with a palpable gap at the coronoid level and weakness of elbow flexion — more subtle than distal biceps avulsion because elbow flexion is maintained by the intact biceps. MRI confirms the avulsion. Surgical reattachment through a single volar incision using suture anchor fixation to the ulnar tuberosity restores full elbow flexion strength. The brachialis must be identified and protected during anterior elbow approaches to the coronoid for terrible triad fracture fixation.

Pathology

Common Injuries & Conditions

Distal Brachialis Avulsion from the Coronoid

Eccentric loading during elbow flexion avulses the brachialis tendon from the coronoid and ulnar tuberosity, producing anterior elbow pain and weakness of elbow flexion that is less dramatic than biceps avulsion; MRI demonstrates the avulsed brachialis tendon and suture anchor reattachment restores full elbow flexion strength.