The pronator quadratus is a muscle within the deep compartment of the anterior forearm. It is a square-shaped muscle which lies deep to the tendons of flexor pollicis longus and flexor digitorum profundus.
- Attachments: Originates from the anterior surface of the ulna and attaches to the anterior surface of the radius.
- Actions: Pronates the forearm.
- Innervation: Median nerve (anterior interosseous branch).
- Blood supply: Ulnar artery