1.5 Arm

Question 1

• comes from lateral cord of brachial plexus, pierces the coracobrachialis
• innervates all 3 flexors of the arm
• ends as lateral cutaneous nerve of forearm

Answer 1

musculocutaneous nerve

Question 2

• injury to this nerve caused by weapons (stabbing)
• paralysis of coracobrachialis, biceps, and brachialis
• weakened forearm flexination and supination
• loss of sensation of lateral surface of forearm

Answer 2

musculocutaneous nerve injury

Question 3

• direct continuation of posterior cord of brachial plexus
• enters anterior to long head of triceps, descends with deep artery of arm
• passes around humerus in radial groove, innervates triceps

Answer 3

Radial nerve

Question 4

-injury before triceps: paralysis of triceps, brachioradialis, supinator and extensor muscles of wrist and digits
-injury after tricep branches:
same but tricep not paralyzed
-wrist drop sign

Answer 4

radial nerve injury

Question 5

• from union of lateral and medial cord
• run lateral to brachial artery,, crosses medial and descend to cubital fossa, runs under bicipital aponeurosis
• innervates elbow joint

Answer 5

median nerve

Question 6

• from medial cord
• medial side of brachial artery, passes posterior to medial epicondyle and olecranon
• “funny bone”, innervates elbow joint

Answer 6

ulnar nerve

Question 7

pronator syndrome, due to heads of pronator teres muscle, pain and tenderness in proximal anterior forearm, Popes hand

Answer 7

median nerve injury

Question 8

ulnar nerve compressed by flexor carpi ulnaris, “claw hand”

Answer 8

cubital tunnel syndrome