Quick Facts
Origin: Anterior aspect of distal one quarter of ulna.
Insertion: Anterior aspect of distal one quarter of radius.
Action: Pronates forearm at radioulnar joints.
Innervation: Anterior antebrachial interosseous nerve (C7-C8).
Arterial Supply: Anterior interosseous artery.
Related parts of the anatomy
Origin
The pronator quadratus muscle originates from the:
- ridge found on the anterior aspect of the distal one quarter of ulna;
- medial part of the aponeurosis that covers it.
Insertion
The fibers of the pronator quadratus muscle travel inferolaterally and insert onto the anterior aspect of the distal one quarter of radius.
Key Features & Anatomical Relations
The pronator quadratus muscle is one of the muscles of the deep part of the anterior compartment of the forearm. It is a flat, quadrilateral type of skeletal muscle. It is located:
- anterior (superficial) to the distal one quarter of the ulna, radius, and interosseous membrane of forearm;
- posterior (deep) to the flexor pollicis longus muscle, and the tendons of the flexor digitorum superficialis and profundus muscles.
Actions & Testing
The pronator quadratus muscle pronates the forearm at the radioulnar joints. It also helps stabilize the connection between the radius and ulna.
The pronator quadratus muscle can be tested by pronating the forearm against resistance while the hand is relaxed. However, due to its deep location in the distal forearm, the pronator quadratus is difficult to palpate, and its action is difficult to discern from that of the pronator teres muscle on physical examination (Standring, 2016).
References
Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.
