Nerve Palsies

Question 1

Define Hilton’s Law?

Answer 1

Any nerve supplying a joint will also supply:

• The muscles moving that joint
• Skin over the insertion of those muscles

Question 2

Infant presents with the classic “Waiters/Porters Tip” position, what is this position?

Answer 2

Shoulder adducted and Internally rotated
Elbow extended and pronated
Wrist flexed

Question 3

What does the “Waiter’s Tip” position suggest pathologically?

Answer 3

Erb’s palsy, Traction of the brachial plexus (specifically C5/6 aka the superior trunk) e.g. during forceps delivery

Question 4

Patient presents with a clawed hand, what injury to the brachial plexus could cause this?

Answer 4

Klumpke’s Palsy, i.e. injury to the Inferior trunk (C8/T1). It affects the small hand muscles

Question 5

Other than Erb’s (sup trunk),Klumpke’s (Inf Trunk) what other common nerve palsies affect the brachial plexus?

Answer 5

Total Brachial Plexus Palsy.

Affecting C5-T1

Question 6

Patient presents with a wasted deltoid and loss of sensation in their regimental badge area. They also mentioned having had a recent fracture of their arm?

Answer 6

Axillary nerve (C5/6) palsy, commonly associated with surgical neck fractures of the humerus and shoulder dislocation.

It supplies the deltoid, teres minor and regimental badge area

Question 7

What does the radial nerve arise from and supply?

Answer 7

C5-T1, arising from the post cord

Supplies:

• Triceps
• Brachioradialis
• ECRL & ECRB
• Finger extensors via PIN
• Posterior hand sensation via SRN

Question 8

How would compression or entrapment of the radial nerve present?

Answer 8

– In axilla: loss of elbow extension, wrist extension and sensory changes forearm and hand
– In arm: loss of wrist extension and sensory loss
– In forearm: loss of finger extension (PIN)
– At wrist: loss of sensation (SRN) eg. handcuffs

Question 9

From where does the median nerve arise and what does it supply?

Answer 9

C5-T1, arises from medial & Lateral cords
Supplies:
- All forearm flexors except FCU & Medial half of FDP
- LOAF muscles in hand
- Sensation to radial 3.5 digits

Question 10

What condition comes with median nerve palsy?

Answer 10

Carpal Tunnel Syndrome

Question 11

What causes carpal tunnel syndrome?

Answer 11

Developmental
Trauma (Distal radial fracture)
Ganglia, fibroma or lipoma swelling
Inflammatory - Gout, rheumatoid, TB or Amyloid
Metabolic - Pregnancy, mucopolysaccharides & Hypothyroidism

Question 12

How does carpal tunnel syndrome present?

Answer 12

Nocturnal pain
Paraesthesia
Abductor Pollicis Brevis weakness 
\+ve Tinnels/Phalen's Signs
Thenar wasting 
scars + deformity

Question 13

Where does the ulnar nerve arise and what does it supply?

Answer 13

C8/T1, arising from medial cord

Supplies FCU & medial 1/2 of FDP
+ Intrinsic hand muscles except LOAF
Sensation to Ulnar 1.5 digits

Question 14

What are the LOAF Muscles?

Answer 14

The only intrinsic hand muscles not supplied by the ulna, they’re innervated by the median nerve:

• Lateral 2 Lumbricals
• Oppenens Pollicis
• Abductor Pollicis Brevis
• Flexor Pollicis Brevis

Question 15

What condition affects the ulnar nerve?

Answer 15

Cubital Tunnel Syndrome

Question 16

What is the cubital tunnel?

Answer 16

Tunnel between medial epicondyle and olecranon with the FCU fascia forming the roof. Contains the ulnar nerve

Question 17

How does Cubital Tunnel Syndrome present?

Answer 17

Numbness on ulnar side of hand and fine dexterity loss
Hypothenar and 4th webspace wasting + guttering
Ulnar claw hand
+ve Froment’s Test (Tests Adductor pollicis)

Question 18

How does Cubital Tunnel syndrome cause a claw hand?

Answer 18

Ulnar claw hand involves hyperextension of the MCPJ and flexion of IPJs

Question 19

Patient presents with acute foot drop and pain under their knee?

Answer 19

FIbula fracture causing Common Peroneal Nerve Palsy

This presetns with Weakness in Dorsiflexion or “Foot Drop”

Question 20

Where does the Common Peroneal Nerve arise?

Answer 20

L4-S2

From the Sciatic nerve (L4-S3) which itself arises from the sacral plexus (L4-S4)

Question 21

Patient experiences altered sensation and pains in their lateral thigh, likely diagnosis?

Answer 21

Meralgia Parasthetica
The Lateral Cutaneous femoral Nerve (a branch of the lumbar plexus) is compressed as it travels under the lateral border of the inguinal ligament

This causes altered sensation and pain in the lateral thigh

Question 22

What is one of the most common causes of downwards traction injury to the brachial plexus

Answer 22

Falling sideways on neck

Question 23

What is one of the most common causes of upwards traction injury to the brachial plexus

Answer 23

Breech delivery: bum first

Question 24

Which are the two most common injuries to nerves?

Answer 24

• Compression

- Entrapment

Question 25

What different types of Palsies present due to damage to the radial nerve

Answer 25

• Saturday Night Palsy
• Honeymoon Palsy
• Crutch Palsy

Question 26

What causes damage to median nerve function?

Answer 26

• Wrist laceration

- Carpal tunnel

Question 27

What is the Ulnar paradox

Answer 27

-A distal lesion has worse clawing than a proximal lesion, due to intact long flexors with a distal lesion

Question 28

Common cause of damage to sciatic nerve

Answer 28

• Dislocation of hip
• IM injection
• Surgery