A All heads:Extend the elbow (humeroulnar joint)Long head:Extend the shoulder (glenohumeral joint)Adduct the shoulder (G/H joint)O Long head: Infraglenoid tubercle of the scapulaLateral head: Posterior surface of proximal half of the humerusMedial head: Posterior surface of distal half of the humerusI Olecranon process of the ulna The primary function is for the extension of the elbow joint Triceps Brachii