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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.

Forearm muscles (colored), Upper extremity, Muscles, Human arm, Anteromedial view, Dorsolateral view
Muscles of forearm by Anatomy Next
Pronator quadratus
OriginDistal anterior surface of ulna
InsertionDistal anterior surface of radius
ActionPronation of forearm
Innervation Anterior interosseous branch of median nerve (C7, C8)
Blood supply Anterior interosseous artery



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



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



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



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.