The pronator teres muscle is one of 4 muscles within the superficial layer of the anterior compartment of the forearm, and is responsible for pronation of the forearm and flexion at the elbow joint.
The other muscles in this layer are the flexor carpi ulnaris, palmaris longus and flexor carpi radialis. It is the most laterally located muscle of the superficial compartment, located lateral to the flexor carpi radialis.
The muscles of the superficial layer share a common origin from the medial epicondyle of the humerus.
The pronator teres has two heads:
- Humeral head (larger and more superficial)
- Ulnar head (thinner and smaller)
Medial epicondyle of the humerus (common flexor origin)
Bases of metacarpals II (index) and III (middle)
Pronator teres, as the name suggests primarily functions to pronate the forearm, turning the hand posteriorly. It is assisted by its distal counterpart within the deep compartment of the anterior forearm muscles – the pronator quadratus.
Due to its mechanical configuration and attachments, it also serves as a weak flexor of the elbow.