Neuropathies

Question 1

What class of neuropathy distribution do diseases, drugs, and toxins usually cause?

Answer 1

Polyneuropathy

Question 2

What class of neuropathy distribution does trauma usually cause?

Answer 2

Mononeuropathy

Question 3

What is paralysis?

Answer 3

Loss of muscular movement

Question 4

What is the difference between complete and incomplete paralysis?

Answer 4

Complete = no movement because all movement-causing muscles have lost innervation

Incomplete = movement possible (but weak) because some movement-causing muscles still have innervation

Question 5

What is anesthesia?

Answer 5

Numbness or loss of cutaneous sensation

Question 6

What does knowing the “course” mean in the context of neuropathy?

Answer 6

The course indicates where the nerve has been injured –> only muscles and skin areas distal to the site of injury will be affected

Question 7

What does knowing the “distribution” mean in the context of neuropathy?

Answer 7

The distribution indicates what muscles and skin have been affected by the injury

Question 8

What is the cause of Erb’s palsy?

Answer 8

Traction or tear of the upper trunk (C5 and C6)

In adults, usually due to a blow to the shoulder producing excessive separation of the neck and shoulder

In newborns, can happen during delivery by pulling a baby out by their head

Question 9

What are the effects of Erb’s palsy?

Answer 9

Paralysis of proximal limb muscles (C5 and C6 myotomes) leading to waiter’s tip position and anesthesia in the C5 and C6 dermatomes on the lateral side of the arm, forearm, and hand

Question 10

What is the cause of waiter’s tip hand?

Answer 10

Loss of flexion, abduction, and lateral rotation of the arm

Loss of flexion of the forearm and weakness of supination

Weakness of wrist extension

Question 11

What causes Klumpke’s palsy?

Answer 11

Traction or tear of the lower (inferior) trunk

In newborns,canbecaused by pulling a baby out by the arm

In adults, grasping something to break a fall

Question 12

What are the effects of Klumpke’s palsy?

Answer 12

Paralysis of distal limb muscles (C8 and T1 myotomes) that primarily affects intrinsic hand muscles innervated by the median and ulnar nerves, resulting in Klumpke’s total claw hand

Question 13

What is the cause of Klumpke’s total claw hand?

Answer 13

Loss of flexion in MCPs (due to interossei and lumbricals) and loss of extension of the proximal and distal interphalangeal joints (due to lumbricals) and paralysis of thenar and hypothenar muscles

Question 14

What are causes of median nerve injuries (C5, 6, 7, 8, and T1)?

Answer 14

Proximal lesions that compress or cut the nerve (ex. pronator syndrome)

Distal lesions (ex. carpal tunnel syndrome)

Question 15

Which hand muscles does the median nerve innervate?

Answer 15

Med. LOAF

L = 1st and 2nd lumbricals

O = opponens pollicis

A = abductor pollicis brevis

F = flexor pollicis brevis

Question 16

What median nerve injuries causes ape hand?

Answer 16

Proximal and distal lesions along the median nerve

Question 17

What median nerve injuries cause hand of benediction?

Answer 17

Proximal lesions along the median nerve –> patient can flex digits 4 and 5, but not digits 2 and 3

Question 18

What median nerve injuries cause median claw hand?

Answer 18

Distal lesions –> weakness of flexion of the index and middle fingers, 4th and 5th fingers are normal (ulnar nerves)

Question 19

What are causes of ulnar nerve injuries?

Answer 19

Proximal lesions: fractures of the medial epicondyle or compression of the ulnar groove or in the cubital tunnel

Distal lesions: can be compressed or cut at the wrist in the tunnel of Guyon or by a fracture of the hook of the hamate

Question 20

What flexor forearm muscles are innervated by the ulnar nerve?

Answer 20

Flexor carpi ulnaris and the medial half of flexor digitorum profundus

Question 21

What are the effects of both proximal and distal lesions along the ulnar nerve?

Answer 21

• loss of adduction and abduction of the fingers
• loss of thumb adduction
• loss of PIP and DIP joint extension
• sensory changes of the dorsal and plamar surfaces on medial side of hand

Question 22

What is the presentation of distal lesions along the ulnar nerve?

Answer 22

Ulnar claw hand of digits 4 and 5 - looks like the hand of benediction, but is caused by loss of extension in the ring and little fingers

Question 23

What is the difference between the hand of benediction injury and ulnar claw?

Answer 23

Hand of benediction = median nerve = patient is asked to FLEX hand but cannot flex index and middle finger

Ulnar claw = ulnar nerve = patient is asked to EXTEND fingers, but ring and little finger cannot extend

Question 24

What is the presentation of proximal lesions along ulnar nerve?

Answer 24

Paralysis of forearm and hand muscles, mild ulnar claw, weakness of wrist flexion

Question 25

What is the cause of apes hand?

Answer 25

Proximal and distal median nerve injuries due to thenar atrophy

Question 26

What are the causes of radial nerve injury?

Answer 26

• fractures of humeral shaft
• compression of the nerve by the back of the chair (Saturday night palsy), someone’s head (honeymoon palsy), and poorly fitting crutches (crutch palsy)

Question 27

What are the effects of radial nerve injury?

Answer 27

• wrist drop due to paralysis of extensor muscles
• anasthesia on radial half of dorsum
• more proximal lesions lead to triceps paralysis (chicken wing due to flexed elbow, wrist, and MCPs)

Question 28

What is the cause of axillary nerve injury?

Answer 28

Fractures of the humeral surgical neck, dislocations of the shoulder joint

Question 29

What are the effects of axillary nerve injury?

Answer 29

Loss of abduction (deltoid) and weakness of lateral rotation (teres minor) of the arm, loss in rounded counter of shoulder, anesthesia over lateral surface of shoulder

Question 30

What are the causes of long thoracic nerve injury?

Answer 30

Commonly injured during surgery or penetrating wounds

Question 31

What are the effects of long thoracic nerve?

Answer 31

Paralysis of serratus anterior, loss of protraction and upward rotation of scapula (leads to winging of scapula)

Question 32

What are causes of musculocutaneous nerve injury?

Answer 32

Penetrating wounds in the axilla

Question 33

What are the effects of musculocutaneous nerve injury?

Answer 33

Weakness of forearm flexion (biceps, brachialis), weakness of supination (biceps) and arm flexion (coracobrachialis, biceps), anaesthesia on lateral forearm (lateral antebrachial cutaneous nerve)

Question 34

following a brachial plexus injury a patent presents with a waiter’s tip position of the upper limb. In what areas of skin would you expect to see anesthesia or loss of sensation?

a) C8, T1 dermatomes
b) medial side of the hand and medial 1 1/2 digits
c) C5, 6 dermatomes
d) lateral side of the hand and lateral 3 1/2 digits
e) medial side of the forearm and hand

Answer 34

C) C5, 6 dermatomes

Question 35

A patient is diagnosed with a distal lesion of the median nerve. Which of the following would you expect to see in this patient?

a) sensory changes on the dorsal and palmar surfaces of the medial side of the hand and medial 1 1/2 fingers
b) loss of thumb flexion and abduction
c) anesthesia in the C5, 6 dermatomes on the lateral side of the arm, forearm, and hand
d) loss of thumb adduction
e) loss of PIP and DIP joint extension of digits 4 and 5

Answer 35

b) loss of thumb flexion and abduction

Question 36

A patient is diagnosed with a distal injury of the ulnar nerve. Which of the following would you expect to see in this patient?

a) pope’s blessing upon finger extension
b) claw hand of digits 2 and 3
c) sensory changes on the dorsal and palmar surfaces of the lateral 3 1/2 digits and adjacent palm
d) claw hand of all 5 digits
e) anesthesia in the C8 and T1 dermatomes along the medial side of the arm, forearm, and hand

Answer 36

a) pope’s blessing upon finger extension
* also called ulnar claw*

Question 37

A patient presents with loss of sensation on the radial half of the dorsum of the hand. What deformity of the hand would you expect this patient to have?

a) ape hand
b) waiter’s tip hand
c) claw hand of digits 4 and 5
d) wrist drop
e) sign of benediction upon finger flexion

Answer 37

d) wrist drop

Question 38

A patient presents with loss of abduction and weakness of lateral rotation of the arm and anesthesia over the lateral surface of the shoulder. These symptoms could result from a nerve injury caused by:

a) mastectomy operation
b) fracture of the humeral surgical neck
c) forceful upward pull of the shoulder during birth
d) fracture of the humeral shaft
e) fracture of the supracondylar humerus

Answer 38

b) fracture of the humeral surgical neck