Corpus: Pronator quadratus muscle

Origin

The pronator quadratus muscle originates from the anterior edge (Margo anterior) of the distal quarter of the ulna. An aponeurosis covering the medial third of the muscle also serves as an origin area.

Insertion

The fibers of the pronator quadratus muscle run laterally and distally to the radius above the interosseous membrane of the forearm, where they find their insertion on the anterior face of the bone in its distal quarter.

The pronator quadratus muscle is innervated by the anterior interosseous nerve, a branch of the median nerve (segments: C6-C8 and Th1).

Along with the pronator teres muscle, the pronator quadratus muscle is the most important muscle for pronation of the forearm.