Brachialis muscle

The brachialis muscle is a muscle of the upper arm that connects the humerus to the ulna and flexes the elbow when contracted. Because it lies deeper in the arm, the motion created by the brachialis is often attributed to the biceps. Flexion of the elbow is caused primarily the brachialis, with support from the biceps.

Origin
The brachialis originates on the anterior lower half of the humerus.

Insertion
The brachialis inserts on two points on the ulna: the coronoid process and the ulnar tuberosity.

Innervation
The brachialis is innervated by the musculocutaneous nerve, C5 and C6, with an additional small supply from the radial nerve, C7.