upper limb muscles

upper limb muscles

1. deltoid - posterior

   • action
     • abducts and externally rotates shoulder
   • origin
     • inferior border of spine of scapula
   • insertion
     • deltoid tuberosity on lateral surface of humerus

2. biceps brachii

   • insertion
     • radial tuberosity and bicipital aponeurosis
   • origin
     • supraglenoid fossa and coracoid process of scapula
   • action
     • flexes, supinates elbow, flexes shoulder

3. triceps brachii

   • origin
     • long head: infraglenoid tubercle of scapula.
     • lateral head: upper half of posterior surface of humerus.
     • distal 2/3 of posterior surfaces of humerus
   • insertion
     • olecranon process of ulna
   • action
     • all heads extend elbow. long head extends and adducts shoulder

4. rhomboids

   • action
     • retracts and medially rotates scapula
   • origin
     • C7-T1, T2-T5
   • insertion
     • medial border of scapula below spine

5. pectoralis major & minor

   • origin
     • major - medial 2/3 of clavicle. minor - anterior surface of ribs 3-5
   • Action
     • major - internal rotation. minor - lateral rotation
   • insertion
     • major - lateral lip of bicipital groove of humerus. minor - corocoid process of scapula