MSK and Skin- First Aid

Question 1

Causes of Erb’s Palsy

Answer 1

Traction or tear of the upper trunk (C5,6) caused by trauma causing excessive separation of the neck and shoulder or during childbirth when the head of the neonate is pulled while the shoulder is stuck in the birth canal

Question 2

Effect of Erb’s Palsy

Answer 2

Nerves damaged (muscle receiving innervation): Musculocutaneous (biceps brachii), Axillary (deltoid), Suprascapular (supra/infraspinatus)
Loss of arm flexion, abduction, lateral rotation–> waiter’s tip
Anesthesia in the lateral arm, fore-arm, and hand

Question 3

Causes of Klumpke’s Palsy

Answer 3

Traction or tear of the lower trunk (C8,T1) caused by grasping on something to prevent a fall or pulling on the neonate’s shoulder during childbirth or compression of the plexus between cervical and 1st rib in thoracic outlet syndrome

Question 4

Effect of Klumpke’s Palsy

Answer 4

Nerves damaged (muscles receiving innervation)
Median and Ulnar (lumbricals and interossei)
Lumbricals extend the PIP and DIP joints and help the interossei flex the MCP joints--> complete loss of these muscles reverses everything--> Klumpke's total claw hand

Question 5

Causes of proximal lesions of the median nerve

Answer 5

Fractures of the supracondylar humerus

Question 6

Causes of distal lesions of the median nerve

Answer 6

Carpel Tunnel Syndrome- swelling of the flexor tendons and their synovial sheaths that run in the tunnel

Question 7

Effects of proximal lesions of the median nerve

Answer 7

Finding (muscles damaged)
Ape hand (loss of opponens pollicis, a thenar intrinsic hand muscle)
Pope’s blessing where lateral fingers can’t be flexed (loss of flexor digitorum superficialis and part of flexor digitorum profundus)
Loss of sensation in the entire palmar surface of the lateral fingers and the distal part of the dorsal surface

Question 8

Effects of distal lesions of the median nerve

Answer 8

Finding (muscles damaged)
Ape hand (loss of opponens pollicis, a thenar intrinsic hand muscle)
Claw hand of digits 2,3 (intact FDS and FDP pull the DIP and PIP joints into flexion while extensors pull MCP into extension because 1st and 2nd lumbricals are paralyzed)

Question 9

Causes of proximal lesions of the ulnar nerve

Answer 9

Medial epicondylar fracture

Compresson in the ulnar groove or between the two heads of flexor carpi ulnaris (cubital tunnel syndrome)

Question 10

Causes of distal lesions of the ulnar nerve

Answer 10

Compression in the tunnel of Guyon

Fracture of the hook of the hamate

Question 11

Effects of proximal lesions of the ulnar nerve

Answer 11

Finding (muscle damaged)
Loss of finger abduction and adduction along with atrophy of the 1st intermetacarpal space (dorsal and palmar interosseous)
Wrist flexion is weak and deviates radially (loss of flexor carpi ulnaris)

Question 12

Effects of distal lesions of the ulnar nerve

Answer 12

Finding (muscle damaged)
Ulnar claw hand (loss of 3rd and 4th lumbricals + interossei while FDP/FDS/extensors are intact)
Loss of sensation of the palmar and dorsal side of the medial fingers

Question 13

Causes of radial nerve injury

Answer 13

Saturday night palsy
Poorly fitting crutches
Fractures of the humeral shaft

Question 14

Effect of radial nerve injury

Answer 14

Finding (muscle damaged)
Wrist drop with inability to extend MCP joints (wrist and finger extensors)
Anesthesia over the proximal part of the dorsal hand

Question 15

Causes of axillary nerve injury

Answer 15

Fractures of the surgical humeral neck

Dislocations of the shoulder joint

Question 16

Causes of long thoracic nerve injury (C5,6,7)

Answer 16

Mastectomy or thoracic surgery

Question 17

Effects of long thoracic nerve injury

Answer 17

Finding (muscle damaged)

Winging of the scapula due to loss of scapular protraction (serratus anterior)