Origin: Humeral head: medial epicondyle of humerus (common flexor tendon)
Artery: Ulnar artery and radial artery
Nerve: Median nerve
Action: Pronation of forearm, flexes elbow
Antagonist: Supinator muscle
The humeral head, the larger and more superficial, arises immediately above the medial epicondyle, and from the tendon common to the origin of the other muscles; also from the intermuscular septum between it and the Flexor carpi radialis and from the antibrachial fascia.