Carpal Tunnel Syndrome

Question 1

What is carpal tunnel syndrome

Answer 1

Due to compression of the median nerve in the carpal tunnel

Question 2

What does a patient with carpal tunnel complain of

Answer 2

Tingling and numbess in thumb, index and middle finger
Worse at night or after repetitive action
Relieved by flicking or shaking

Question 3

What might you find on inspection of a patient with carpal tunnel syndrome

Answer 3

Wasting of the thenar eminence (in advanced cases)

Scar from previous surgery over the transverse carpal ligament on wrist

Question 4

What is the autonomous sensory area of the hand supplied by the median nerve

Answer 4

Distal phalanges of index and middle fingers

Question 5

What is the autonomous sensory area of the hand supplied by the ulnar nerve

Answer 5

Middle and distal phalanges of the little finger

Question 6

What is the autonomous sensory area of the hand supplied by the radial nerve

Answer 6

Over the first dorsal interosseus muscle (but usually there is no autonomous zone)

Question 7

What muscles are innervated by the median nerve

Answer 7

LOAF

Lateral two lumbricals
Opponens pollicis (thumb touching the little finger)
Abductor pollicis brevis (abduction of the thumb - moving it anteriorly)
Flexor pollicis brevis

Question 8

What muscle is purely supplied by the median nerve

Answer 8

Abductor pollicis brevis

Question 9

What muscle are purely supplied by the radial nerve

Answer 9

Metacarpophalangeal extensors - extension of the fingers at the knuckles

Question 10

What are the special tests for carpal tunnel

Answer 10

Tinel’s sign
Phalen’s test
Duran test (flexion compression test)

Question 11

What is Tinel’s sign

Answer 11

Tinel’s Tapping

Tapping over the median nerve at the wrist reproduces tingling sensation in the distribution of the median nerve (first three fingers)

Question 12

What is Phalen’s test

Answer 12

Maximal flexion of the wrist for 1 min exacerbates symptoms which are promptly relieved when flexion stops

Question 13

What is the flexion compression test

Answer 13

Maximal flexion of the wrist with digital compression of the median nerve at the wrist reproduces symptoms (if symptoms appear within 20s = positive)

Question 14

What are the causes of carpal tunnel syndrome

Answer 14

Most common is idiopathic

Anatomical abnormalities of bone - wrist fractures, acromegaly
Anatomical abnormalities of soft tissue - lipomas, ganglia
Inflammatory - RA, gout
Alterations of fluid balance - pregnancy, menopause, hypothyroidism
Neuropathic conditions - DM, alcoholism