Pronator quadratus

The pronator quadratus (Latin: musculus pronator quadratus) is a quadrangular-shaped flat and thin muscle of the upper limb that extends between the distal aspects of the radius and ulna. It belongs to the anterior muscles of the forearm. The pronator quadratus lies deep within the fourth layer of the anterior forearm compartment.

Origin

The pronator quadratus muscle originates from the distal anterior surface of the ulna.

Insertion

The pronator quadratus goes in the lateral direction and inserts on the distal anterior surface of the radius.

Action

The pronator quadratus muscle provides the pronation of the forearm at the distal radioulnar joint.

Innervation

The pronator quadratus is innervated by the anterior interosseous nerve of the median nerve (C7, C8).

Blood supply

The pronator quadratus muscle receives arterial blood supply from the anterior interosseous artery - a branch of the common interosseous artery.