peripheral nerve injuries

Question 1

what nerve roots are damaged in erbs palsy (upper brachial plexus injury)?

Answer 1

C5 and C6

Question 2

what nerve roots are damaged in klumpke’s paralysis (lower brachial pleus injury)?

Answer 2

• C8 & T1

Question 3

what roots does the long thoracic nerve come off?

Answer 3

C5, C6, C7

Question 4

what can cause erbs palsy?

Answer 4

widening of the angle between the neck and shoulder

Question 5

what is the deformity seen with erbs palsy & why?

Answer 5

• waiters tip
• C5 & C6 damaged - lateral cord damaged - musculocutaneous and median nerve damaged - unable to flex arm and forarm and wrist - so arm 7 wrsit stays in an extended position

Question 6

what can cause klumpke’s paralysis?

Answer 6

an increased angle between the trunk and arm

Question 7

what deformity is seen with klumpke’s paralysis?

Answer 7

a claw hand

Question 8

what structures does the median nerve provide motor innervation/ function to?

Answer 8

• flexor muscles in forearm EXCEPT FCU and 1/2 of FDP
• first & second lumbricals
• muscles of thenar eminence (thumb) - OAF

Question 9

what would a disability of the median nerve look like - what symptoms might the patient have?

Answer 9

• wasting of thenar eminence
• ape like hand
• loss of opponens muscle

Question 10

what is a good test to test for median nerve injury?

Answer 10

• ask the patient to oppose their thumb - they should be unable to with a median nerve injury

Question 11

what are examples of situations that could cause a median nerve injury?

Answer 11

• laceration (cut) at elbow
• fractures at elbow
• laceration at the wrist
• carpel tunnel syndrome (compression of the median nerve)

Question 12

what kind of symptoms can be seen with carpal tunnel syndrome?

Answer 12

• pins and needles
• burning pain
• possible wasting of thenar eminence over time
• most patients with this syndrome have normal power and may have symptoms but no signs

Question 13

what muscles does the ulnar nerve provide motor innervation to?

Answer 13

• flexor carpi ulnaris and 1/2 of FDP
• hypothenar eminence
• interossei muscles
• adductor pollicis

Question 14

what are examples of ulnar nerve motor disability symptoms?

Answer 14

• partial claw hand
• wasting of the hypothenar eminence
• wasting of the interossei
• loss of DAB & PAD
• loss of adduction of thumb

Question 15

what is a partial claw hand?

Answer 15

partial clawing of the litte and ring finger

Question 16

how can the adductor pollicus muscle be tested?

Answer 16

• froments test
• ask the patient to pinch a piece of paper between the thumb and index finger
• if an ulnar nerve injury is present, the patient will flex their thumb - showing weakness of adductor pollicis

Question 17

what is the ulnar nerve paradox?

Answer 17

• this refers to the difference in severity of ulnar nerve injury between a lesion at the elbow compared to the wrist
• lesion at or above the elbow - causes loss of flexor digitorum profundus - therefore loss of flexion at the IP joints
• a lesion at the wrist would cause weakness of the hand muscles

Question 18

what are examples of situations that could cause axillary nerve lesions?

Answer 18

• dislocated shoulder
• fracture of the surgical neck of the humerus
• deltoid injections - paralysis of deltoid or loss of sensation over the regimental patch

Question 19

what is the regimental patch?

Answer 19

a patch of skin at the top of the upper arm

Question 20

what are examples of situations and conditions that could cause radial nerve injuries?

Answer 20

• fracture of the midshaft of the humerus
• crutch palsy (compression of the nerve caused by crutches)
• saturday night palsy - prolonged direct pressure on the axillary region

Question 21

what are examples of disabilities that are seen with radial nerve injuries?

Answer 21

• wrist drop - due to the loss of the wrist extensors
• if lesion is high in humerus then also loss of elbow extension
• poor grip

Question 22

what is the sensory distribution of the median and ulnar nerve on the palmar surface of the hand?

Answer 22

• median - palmar surface of thumb, index and middle finger, half of ring finger
• ulnar - half of the ring finger and little finger

Question 23

Describe the sensory innervation of the dorsal surface of the hand

Answer 23

• radial nerve - supplies the dorsal surface of the thumb, index, middle and half of the ring finger
• the ulnar nerve supplies the dorsal surface of the little finger and half the ring finger