106 PART 2 Clinical Kinesiology and Anatomy of the Upper Extremities 12. For eac
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Question
106 PART 2 Clinical Kinesiology and Anatomy of the Upper Extremities 12. For each motion listed, check the muscleís) that is/are the major contributors to the mot Motion Flexion Extension Pronation Supination Biceps Brachialis Triceps Supinator Brachioradialis Pronator teres Pronator quadratus C. Is gravity producing the force for the 13. A. Which nerve innervates the elbow flexors? movement or the resistance to the movement? Which nerve innervates the elbow extensors? B. The nerves that follow pass through the elbow joint. Indicate each nerve's to the elbow joint. D. Which major muscle group is the agonist? Anterior Posterior Ulna: E. Is the agonist acting to.overcome gravity or to Median:Anterior Posterior form elbow action of the down motion slow down gravity? a push-up from the prone position. F. Is the agonist performigg a, concentric or an eccentric contraction? he movement with or against gravity?Explanation / Answer
Ans 12-) Contribution of various muscles of upper extremity in different motions.
Flexion- It is the motion where angle between two joints is decreased and in elbow flexion the angle between forearm and upper arm is decreased. Primary flexor of elbow is Brachialis , however long biceps brachi muscle superficial to Brachialis also flexes elbow but other functions are also carried out. Third is the brachioradialis muscle for elbow flexion and runs from distal end of humerus to distal end of radius.
Main flexors of forearm are Brachialis , Biceps brachi and Brachioradialis.
Extension- Extension is opposite motion where the angle between forearm and arm is increased. Main extensor of forearm is Triceps brachi . It is a long muscle that runs posterior to humerus from scapula to olecranon process of ulna. Anconeus is small muscle that also help in extension alongwith triceps.
Pronation- It is the rotational movement of forearm in which the the palm faces backwards and downwards. Major muscles that causes pronation are Pronator teres that originates from medial epicondyle of humerus and coronoid process of ulna and inserts into the middle of lateral surface of radius. Pronator quadratus is deep to pronator teres and originates from anterior surface of shaft of ulna and inserts into anterior border of radius and traingular area above ulnar notch.
Supination- It is opposite motion of pronation in which rotation of forearm and hand is such that the palm faces upwards. Supinator and Biceps brachi brings about supination. supinator muscle always acts alongwith biceps to cause supination.
Ans 13 A-) Nerve that innervates elbow flexors ( Biceps , brachialis ) is Musculocutaneous nerve (C5,6) Brachioradialis is innervated by Radial nerve ( C5 , 6).
Innervation of elbow extensors (Triceps ) is by Radial nerve (C7 , 8).
B) Ulnar nerve ---- It runs in anterior or flexor compartment of forearm between two heads of muscle Flexor carpi ulnaris. Posteriorly in forearm it passes Posterior to medial epicondyle of humerus.
Median nerve -----Anteriorly it enters the cubital fossa medial to brachialis tendon and posteriorly it enters the forearm between two heads of pronator teres muscle. It is the only nerve that passes through the carpal tunnel.
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