Peripheral nerve palsies - Upper limb

Question 1

Aetiology of Peripheral Nerve Injury

Answer 1

Question 2

Pathophysiology of nerve compression

Nerve palsy S/S

Answer 2

Question 3

Classification of Nerve Injury

Answer 3

Question 4

Median nerve

Anatomy

Answer 4

Question 5

Median nerve

Function

Answer 5

Thenar muscle wasting is a late sign
APB palsy is the most specific for median nerve
Lay hand flat on table and lift thumb to ceiling, do not lift thumb in a handshake position as that tests APL

Question 6

Median nerve palsy

Causes

Answer 6

Pronator teres is high palsy
CTS is low palsy - less sensory deficit and fewer muscle involvement
Carpal bone perilunate fracture is also possible

Question 7

Median nerve palsy

Clinical presentation
Special tests

Answer 7

5 digit dumbness is also possible due to cross innervation
More than 3.5 fingers is also compatible with CTS
Palmar cutaneous branch doesnt cross the tunnel, and true CTS only causes digital numbness and not palmar numbness

Question 8

Ulnar nerve

Course

Answer 8

Question 9

Ulnar nerve

Function

Answer 9

Dorsal cutaneous nerve branches before Guyons canal
So dorsal numbness is damage higher than Guyons canal, thus high ulnar nerve palsy

Question 10

Causes of ulnar nerve palsy

Answer 10

Elbow deformities: Cubitus valgus or varus, OA, RA elbow
Cubital tunnel syndrome is most common
Guyon canal palsy: crutch users, low bicycle handle bar road cyclists

Question 11

Ulnar nerve palsy

Clinical presentation

Answer 11

Also Jeanne sign
Compensated by MCPJ hyperextension by EPL by radial nerve

Froment sign - look for flexion of IP joint to cheat when pinching with extended IP joint

Other signs
Crossed finger test for 1st palmar and 2nd dorsal interossei weakness
Dorsal interossei palsy
Pollock test

Provocative test:
Elbow flexion test - to provoke symptoms
Tinel sign over elbow
Ulnar nerve subluxation above medial epicondyle and snapping below medial epicondyle (require surgery)

Question 12

Radial nerve

Course

Answer 12

Question 13

Radial nerve

Function

Answer 13

Sensory of posterior arm and dorsum

Question 14

Radial nerve palsy

Causes

Answer 14

Question 15

Radial nerve palsy

Clinical presentation

Answer 15

EDC test may be cheated by lumbricals supplied by median nerve
Ask patient to make a claw hand then test MCPJ extension

Question 16

Erb’s palsy

Etiology
Clinical presentation
Management

Answer 16

Question 17

Klumpke’s palsy

Cause
Signs

Answer 17

Question 18

Brachial plexus injury

Classification
Features of pre-ganglionic lesion

Answer 18

Question 19

Prognosis of nerve injury

Answer 19

Good prognostic factors

Young Age most important
Low velocity injury, sharp cut
Distal injury

Crush, high velocity, associated vascular damage are poor prognostic factors

Growth:
Nerve growth velocity is 1mm per day for distal nerve damage
Proximal nerve damage may never recover

Question 20

Nerve repair

Answer 20

Question 21

Nerve repair apart from suture

Answer 21

Question 22

Nerve damage diagnosis

Answer 22

Only for ruling out other neuropathic conditions, not for diagnosis of nerve palsy

Question 23

Median nerve AIN branch test

Question 24

Median nerve AIN branch test

Question 25

Benediction sign

Question 26

Median nerve high vs low palsy

Question 27

Median nerve high vs low palsy

Question 28

Ulnar nerve high vs low palsy

Question 29

Ulnar nerve treatment

Answer 29

Question 30

Radial nerve high vs low palsy

Question 31

Foot drop lesion causes

Answer 31

Deep peroneal nerve
Common peroneal nerve
Sciatic nerve
Root
Spine

Foot dorsum numbness and foot drop - likely common peroneal nerve palsy

Question 32

Foot drop lesion causes

Answer 32

Deep peroneal nerve
Common peroneal nerve
Sciatic nerve
Root
Spine

Foot dorsum numbness and foot drop - likely common peroneal nerve palsy

Question 33

L5 root vs peroneal nerve palsy