Peripheral Nerves

Question 1

Function of the axon

Answer 1

Enable sensory neuron to transmit signals from the sensory receptor to the brain

Question 2

Schwann cells location and ourpose

Answer 2

Create the myelin sheath around the axon in the PNS.

Make nerve growth factor which enables the nerve to regenerate

Question 3

Perineurium

Answer 3

Strong elastic tissue that surrounds each fascicle and diffuses input
–blood nerve barrier–

Question 4

2 pathological responses to nerve damage

Answer 4

Demyelination and axonal loss

Question 5

How long do sensory end organs remain viable after injury

Answer 5

6-9 months

Question 6

Sunderland type 3

Answer 6

Involvement of external connective tissue layers

Question 7

Sunderland type 2

Answer 7

Axonotmesis, axons distal to lesion degenerate

Prognosis is good with axonal regeneration because endoneurial tunes remain intact

Question 8

Sunderland type 1

Answer 8

Neuropraxia, with damage to myelin sheaths resulting in local conduction block

Example is Saturday night palsy

Resolved in weeks to months

Question 9

Sunderland type 4

Answer 9

Destruction to the Perineurium

Poor prognosis without surgery because of scar tissue

Surgery might be resection of fibrotic segment of nerve trunk, and repair with graft

Question 10

Sunderland type 5

Answer 10

Neurotmesis, laceration of nerve trunk.

Complete injury- no recovery without surgery

Question 11

Soma

Answer 11

Nerve cell body- must be viable for nerve to work or heal

Question 12

Bergers test

Answer 12

Limericks involvement in carpal tunnel

Hold full fist with wrist neutral for 30-40 sec- pain and parasthesias

Question 13

Ulnar nerve order of innervation

Answer 13

Fcu 
Fdp 
Palmar is brevis
Abductor DQ
Opponens DQ
flexor DQ
Lumbricals 3-4
Palmar interossei 
Dorsal interossei
Adductor pollicis

Question 14

Median nerve order of innervation

Answer 14

Pronator teres
Fcr 
PL
Fds
(Ain below)
Fdp 2-3
Fpl 
Pronator quadratus
(Palm below)
Abductor pollicis brevis
Opponens pollicis
Fpb 
Lumbricals 1-2

Question 15

Radial nerve order of innervation

Answer 15

Triceps
Anconeus 
Brachioradialis 
Ecrl 
Ecrb 
(Pin below)
Supinator
Extensor digitorum 
Edm 
Ecu
Abd pollicis longus 
Extensor pollicis brevis
Extensor indicis

Question 16

Protective immobilization time after nerve repair

Answer 16

Approxmately 7-10 days

Question 17

Hansen’s disease

Answer 17

Used to be leprosy 
Infectious bacterial disease 
Ulnar median and radial nerves are affected
Sensory loss followed by motor loss
Curable with oral chemo

Question 18

Nerve regeneration per month

Answer 18

About 1 inch

Question 19

Upper arm regeneration speed

Answer 19

About 8.5mm per day

Question 20

Final nerve recovery after repair of nerve at wrist

Answer 20

2 years

Question 21

Sites of compression around Pronator

Answer 21

Ligament of struthers
Deep head of Pronator teres
Lacertus fibrosis

Question 22

ways to tell its Pronator syndrome not carpal tunnel

Answer 22

No nocturnal pain

Decreased sensation in thenar space

Question 23

Way to tell its ain involvement not Pronator or carpal tunnel

Answer 23

Weakness in thumb index and middle finger, no parasthesias

Question 24

Duchenne

Answer 24

Clawing of sf and rf

Question 25

Egawa

Answer 25

Inability to abduct middle finger at the MP joint

Question 26

Andre Thomas

Answer 26

Wrist falls into flexion during during middle finger extension

Question 27

Masse

Answer 27

Flattening of the metacarpal arch

Question 28

Test for AIN syndrome

Answer 28

Pinch grip test- maintains tip to tip pinch rather than pad to pad