Muscles that Move the Arm

Question 1

Latissimus dorsi

Answer 1

Action: Prime mover of arm extension

Origin: Thoracic vertebrae, ribs, and iliac crest
Insertion: Humerus

Question 2

Pectoralis major

Answer 2

Action: Agonist of arm flexion

Origin: Medial clavicle, body of sternum, ribs
Insertion: Humerus

Question 3

Deltoid

Answer 3

Action: Arm abduction, flex, extend, and rotate arm

Origin: Acromial end of clavicle, scapula
Insertion: Deltoid tuberosity of humerus

Question 4

Rotator cuff

Answer 4

Action: Rotates, abducts, and adducts arm

Origin: Scapula
Insertion: Humerus