Definition

By: Gregory R. Waryasz, MD

The pronator quadratus muscle of the musculoskeletal system is characterized by being the deepest muscle in the anterior forearm.

It is part of the forearm.  It consists of skeletal muscle fibers.

Its unique structural features include its quadrangular shape.  It lies directly over the radius and ulna.

The origin is the distal quarter of the anterior ulna.

The insertion is the distal quarter of the anterior radius.

The blood supply is from the anterior interosseous artery and venous drainage is from the accompanying veins.

The innervation is from the anterior interosseous nerve.

The pronator quadratus muscle as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.

The function of the pronator quadrates is to pronate the forearm.  The deep fibers help to bind the radius and ulna.  The synergist is the pronator teres.

There are no common diseases.

Commonly used diagnostic procedures include clinical history, physical exam, x-ray, and MRI.

References

Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.

Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.

Wheeless’ Textbook of Orthopaedics: Pronator Quadratus (http://www.wheelessonline.com/ortho/pronator_quadratus)