Action: Extends elbow. Long head stabilizes shoulder joint. medial head retracts capsule of elbow joint on extensionOrigin - 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 septaInsertion - Posterior part of upper surface of olecranon process of ulna and posterior capsuleInnervation - Radial nerve (C7, 8) (from posterior cord ), four branches

1.
Action: Extends elbow. Long head stabilizes shoulder joint. medial head retracts capsule of elbow joint on extension
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
Innervation - Radial nerve (C7, 8) (from posterior cord ), four branches

Triceps
Serratus Anterior
Flexor Hallucis Longus
Pectoralis Major