TRICEPS

ORIGIN
Long head: infraglenoid tubercle of scapula. lateral head: upper half posterior humerus (linear origin). medial head: lies deep on lower half posterior humerus inferomedial to spiral groove and both intermuscular septa
INSERTION
Posterior part of upper surface of olecranon process of ulna and posterior capsule
ACTION
Extends elbow. Long head stabilizes shoulder joint. medial head retracts capsule of elbow joint on extension
NERVE
Radial nerve (C7, 8) (from posterior cord ), four branches