Arm

Arm

1. Posterior

   • innaervated by the radial nerve
     • Triceps brachii
       • Lateral
       • Medial
       • Long head
       • chief extensor of forearm; long head resists dislocation of humerus; especially important during aduction
     • Anconeus
       • assits, triceps in extending forearm; stabilizes elbow joint; may abduct ulna during pronation

2. Anterior

   • Innervated by the musculocutaneous nerve
     • Biceps brachi
       • Short head
       • long head
       • supinates forearm and when in supine flexes forearm; short head resists dislocation of shoulder
     • coracobrachialis
       • helps flex and adducts arm; resists dislocation of shoulder
     • brachialis
       • Flexes forearm in all positions