Monday, 12 May 2014

Pronator Quadratus: a forearm pronator


Pronator: hinting that it can perform the muscle action of pronation.
Quadratus: referring to its 4 corners / square-like shape

Pronator Quadratus lives deep in your wrist -underneath the cord-like tendons of the wrist flexor muscles. It attaches itself to the ends of both forearm bones on the inside of the wrist - so it's actually the deepest on the anterior side

I like to think of this muscle as the lil' sister of last week's larger pronator - Pronator Teres 

 Attachment points:

Origin: Distal 1/4 of the anterior shaft of the ulna
Insertion:  Distal 1/4 of the anterior shaft of the radius

see bony landmarks at end of this post :)

 Muscle Actions:
pronation of the forearm at the radio-ulnar joint

Pronation of the forearm is the act of flipping your hand from palm up to palm down.  This turning actually action happens at the radio-ulnar joint, which is located just below the elbow

*As I hinted above, this muscle helps out with pronation, leaving most of the work to big sister Pronator Teres

We'll end with some bony landmarks !