The supinator is one of the muscles of the deep layer of the posterior compartment of the forearm. The supinator muscle wraps itself around the proximal radius enabling its function in supinating the forearm.
The posterior compartment of the forearm consists of a superficial layer (7 muscles) and a deep layer (5 muscles).
All the muscles of the posterior compartment are innervated by the radial nerve.
The muscles of the deep layer include:
2 heads – superficial and deep
Pronator teres and pronator quadratus