Triceps Brachii

Origin = The Tripeps has two head, a long head and short head. Since the long head is the only portion which crosses the GH joint, we are only going to mention this part as a shoulder muscle.

Long head - just below the glenoid fossa.

Insertion =

Olecranon process of the ulna.

Action =

Long head - Extends and adducts the GH joint.

 

Note: This is primarily an arm extendor at the elbow joint.