Triceps Brachii
Shoulder & Arm
Makes up about 2/3 of your upper arm mass — bigger than biceps!
Function
Extends elbow, long head assists in shoulder extension/adduction
Origin
Long head: infraglenoid tubercle; Lateral head: posterior humerus above radial groove; Medial head: posterior humerus below radial groove
Insertion
Olecranon process of ulna
Innervation
Radial nerve (C6-C8)