Brachialis

Brachialis is a flexor muscle in the upper arm. It lies deep to biceps brachii, and is a more powerful flexor of the elbow.

Brachialis arises from the anterior surface of the humerus, particularly the distal half of this bone. It attaches distally at the coronoid process and the tuberosity of the ulna. The ulna does not rotate, so brachialis's only action is flexion. Pronation/supination of the forearm does not affect its action.

As in the biceps, nervous supply is from the musculocutaneous nerve[?], and blood is supplied by branches of the brachial artery.