Relier Pairs Muscle Actions Part One (D)Version en ligne muscles par Jennifer Jennings 1 flexor carpi radialis and ulnaris 2 deltoid 3 biceps brachii 4 levator scapulae 5 pectoralis major 6 triceps brachii 7 latissimus dorsi 8 trapezius 9 sternocleidomastoid 10 rectus abdominis flexes wrist anteriorly elevates scapula if cervical vertebrae are fixed., flexes neck laterally when scapula is fixed. extends and laterally flexes the neck. extends elbow flexes waist and compresses abdominal viscera flexes, adducts, and medially rotates humerus ant. fibers flex and medially rotate arm, lat. fibers abduct the arm, post. fibers extend and laterally rotate the arm adducts and medially rotates humerus, extends the shoulder joint elbow flexion, forearm supination. rotates head left and right. bilaterally draws head forward and down.