Pronator quadratus muscle

Pronator quadratus muscle

Anterior view of left forearm. Deep muscles. (Pronator quadratus visible at bottom-center right.)
Details
Latin Musculus pronator quadratus
medial, anterior surface of the ulna
lateral, anterior surface of the radius
anterior interosseous artery
median nerve (anterior interosseous nerve)
Actions pronates the forearm
Antagonist
 Supinator muscle
Identifiers
Gray's p.449
Dorlands
/Elsevier		 m_22/12550251
TA A04.6.02.038
FMA 38453
Anatomical terms of muscle

Pronator quadratus is a square shaped muscle on the distal forearm that acts to pronate (turn so the palm faces downwards) the hand.

As it is on the anterior side of the arm, it is innervated by a branch of the median nerve, the anterior interosseous nerve (roots C8 and T1 with T1 being primary). Arterial blood comes via the interosseous artery.

Structure

Its fibers run perpendicular to the direction of the arm, running from the most distal quarter of the anterior ulna to the distal quarter of the anterior radius. It is the only muscle that attaches only to the ulna at one end and the radius at the end.

Function

When pronator quadratus contracts, it pulls the lateral side of the radius towards the ulna, thus pronating the hand. Its deep fibers serve to keep the two bones in the forearm bound together.

Additional Images

External links