Altered sensation and weakness

Question 1

Hand nerve distributions (median, radial, ulnar)…

Answer 1

Question 2

What is carpal tunnel syndrome?

Answer 2

• CTS results from compression of the median nerve as it passes through the carpal tunnel at the wrist
• (the carpal tunnel is formed by the space between the transverse carpal ligament and the carpal bones)

Question 3

What are some conditions which predispose to carpal tunnel syndrome?

Answer 3

• diabetes mellitus
• hypothyroidism
• rheumatoid arthritis
• pregnancy
• acromegaly (excess growth hormone production)
• trauma (eg. wrist fractures)

Question 4

What are the clinical features of carpal tunnel syndrome?

Answer 4

• pain and/or paraesthesia in the median nerve distribution (can radiate distally to fingers or proximally to the elbow)
• thenar muscle strength decreases in advanced disease

Question 5

What investigations should be done for carpal tunnel syndrome?

Answer 5

• Phalen test
• Tinel test
• (nerve conduction studies)

Question 6

What is the management for carpal tunnel syndrome?

Answer 6

• wrist splint, corticosteroid injection
• surgical decompression (by division of the carpal transverse ligament)

Question 7

What is vibration white finger (aka. HAVS)?

Answer 7

• HAVS = hand arm vibration syndrome
• a secondary form of Raynaud’s (thought to be caused by continual industrial exposure to vibration)

Question 8

What are the symptoms of HAVS (vibration white finger)?

Answer 8

• tingling/numbness in digit tips
• excessive whiteness in cold
• reperfusion pain (when blood supply returns to tissue after a period of ischemia)

Question 9

What is ulnar nerve entrapment (cubital tunnel syndrome)?

Answer 9

• when the ulnar nerve becomes compressed as it passes behind the medial epicondyle or through Guyon canal in the wrist

Question 10

What are some predisposing factors to cubital tunnel syndrome?

Answer 10

• local trauma (eg. fractures of the elbow)
• prolonged leaning on the elbow
• elbow synovitis

Question 11

What are the clinical features of cubital tunnel syndrome?

Answer 11

• pain and/or paraesthesia in the medial side of the elbow, which radiates to the medial side of the hand and the ulnar nerve distribution
• pain often exacerbated by elbow flexion
• may result in atrophy of the hypothenar eminence and intrinsic muscles of the hand (majority of which are supplied by the ulnar nerve)
• in severe cases, ulnar clawing of the hand can occur

Question 12

What investigations should be done for cubital tunnel syndrome?

Answer 12

• palpation of the nerve behind the medial epicondyle may provoke symptoms
• (nerve conduction studies)

Question 13

Ulnar clawing of hand…

Answer 13

Question 14

What is the management for cubital tunnel syndrome (ulnar nerve palsy)?

Answer 14

• corticosteroid injection
• surgical decompression (if sensory symptoms persist or if there’s muscle wasting)

Question 15

What is radial nerve palsy (‘Saturday night palsy’)?

Answer 15

• compression of the radial nerve at the axilla

Question 16

What are the predisposing factors to radial nerve palsy (Saturday night palsy)?

Answer 16

• typically an intoxicated patient who falls asleep with their arm hanging over the back of a chair (‘Saturday night palsy’)
• fractures of the humeral shaft

Question 17

What are the clinical features of radial nerve palsy (Saturday night palsy)?

Answer 17

• wrist drop (wrist extensors are paralysed)
• reduced grip strength (wrist flexors do not function well when wrist is in a flexed position)
• paralysis of the triceps
• sensory loss in the radial nerve distribution

Question 18

What is the management for radial nerve palsy?

Answer 18

• wrist splint
• fracture/dislocation reduction can provide relief
• (if no solution then tendon graft or nerve graft indicated)

Question 19

What is common peroneal nerve palsy?

Answer 19

• the common peroneal nerve wraps around the neck of the fibula, and is in a vulnerable position

Question 20

What are the predisposing factors to a common peroneal nerve palsy?

Answer 20

• it may be damaged by fractures of the neck of the fibula
• or pressure from a tight bandage or plaster cast

Question 21

What are the clinical features of a common peroneal nerve palsy?

Answer 21

• foot drop (plantar flexed and inverted): caused by paralysis of ankle/foot extensors
• high-stepping gait (due to foot drop)
• loss of sensitivity over the anterior and lateral aspects of the leg and dorsum of the foot and toes

Question 22

What is the management for a common peroneal nerve palsy?

Answer 22

• pressure on nerve should be relieved and splint applied
• nerve-conduction studies

Question 23

What are the motor function and sensory function of the axillary nerve?

Answer 23

• motor function: innervates teres minor and deltoid muscles
• sensory function: ‘regimental badge’ area

Question 24

What does scapular winging suggest there is damage to?

Answer 24

• long thoracic nerve damage
• (long thoracic nerve derives from the brachial plexus)

Question 25

All the muscles in the hand are supplied by the ulnar nerve, except LOAF which are supplied by the median nerve…

Answer 25

• L : lateral two lumbricals
• O : opponens pollicis
• A : abductor pollicis brevis
• F : flexor pollicis brevis