MUSCLES-DEEP POSTERIOR COMPARTMENT OF FOREARM, PART 1

SUMMARY

1. ANCONEUS - arises from the lower lateral epicondyle. Inserts into the lateral side of the olecranon. Supplied by the radial nerve. Muscle produces a small amount of extension & abduction of the ulna. 
2. SUPINATOR - deep part arises from the supinator crest, wraps horizontally around the radius to insert into the area b/w the anterior & posterior oblique lines. Superficial part arises from the lateral epicondyle, radial collateral ligament of elbow & behind the supinator crest to insert above the anterior oblique line. The PIN passes through both heads to reach the extensor compartment. Supinates the forearm. 

All deep extensors (other than ANCONEUS) are supplied by the PIN.

Reference(s)

R.M.H McMinn (1998). Last’s anatomy: regional and applied. Edinburgh: Churchill Livingstone.
Gray, H., Carter, H.V. and Davidson, G. (2017). Gray’s anatomy. London: Arcturus.