Brachialis Tendon

tendo musculi brachialis

The brachialis tendon is a short, broad tendon arising from the distal fibres of the brachialis muscle and inserting on the ulnar tuberosity and the coronoid process of the ulna. Unlike the biceps brachii, the brachialis inserts directly into the ulna, making it a pure elbow flexor unaffected by forearm rotation position. It is the strongest elbow flexor across all forearm positions.

Region: Forearm

Clinical Relevance

Clinical Notes

Brachialis tendon avulsion is rare but occurs with forced extension injuries or electric shock causing sustained muscle contraction. It can be mistaken for biceps rupture clinically since both produce anterior elbow swelling and flexion weakness. MRI distinguishes the two. The anterior interosseous nerve and brachial artery are at risk during surgical exposure of the brachialis. Myositis ossificans of the brachialis is a specific complication of posterior elbow dislocation.

Pathology

Common Injuries & Conditions

Brachialis Tendon Avulsion

Rare avulsion from the ulnar tuberosity following forced elbow extension, producing anterior elbow pain, swelling, and elbow flexion weakness with a mass at the elbow crease; MRI differentiates from distal biceps tendon rupture and guides surgical reattachment.

Myositis Ossificans

Heterotopic ossification within the brachialis muscle belly following elbow dislocation or repeated elbow trauma, limiting elbow flexion and extension; treated with observation and, if limiting function, delayed surgical excision after maturation of the lesion.