Brachialis
Shoulder & Arm
The brachialis is the “hidden workhorse” of elbow flexion. The biceps gets most of the attention, but the brachialis is often considered the strongest pure flexor of the elbow because it only focuses on bending the elbow.
Function
Flexes the forearm at the elbow. It works in any forearm position — palm up, down, or sideways.
Origin
Distal half of the anterior surface of the humerus, especially near the deltoid tuberosity and the medial/lateral intermuscular septa.
Insertion
Ulnar tuberosity and coronoid process of the ulna.
Innervation
Musculocutaneous nerve (mainly C5–C6); the lateral part may also receive a contribution from the radial nerve.