carpal tunnel

Question 1

which nerves are affected?

Answer 1

median nerve, so numbness is in the median nerve distribution

Question 2

what causes carpal tunnel syndrome?

Answer 2

Compression of the contents of the carpal tunnel (causing carpal tunnel syndrome) is the result of either:

• Swelling of the contents (e.g., swelling of the tendon sheaths due to repetitive strain)
• Narrowing of the tunnel

Question 3

which muscles receive motor innervation from the median nerve?

Answer 3

the thenar muscles:

Abductor pollicis brevis (thumb abduction)

Opponens pollicis (thumb opposition – reaching across the palm to touch the tips of the fingers)

Flexor pollicis brevis (thumb flexion)

Question 4

what are the key risk factors for carpal tunnel syndrome?

Answer 4

Repetitive strain
Obesity
Perimenopause
Rheumatoid arthritis
Diabetes
Acromegaly
Hypothyroidism

Question 5

what is the sensory distribution of the median nerve?

Answer 5

Thumb
Index and middle finger
The lateral half of ring finger

Question 6

what are the special tests to do for carpal tunnel syndrome?

Answer 6

Phalen’s test involves fully flexing the wrist and holding it in this position.

Tinnel’s test involves tapping the wrist at the location where the median nerve travels through the carpal tunnel.

TOM TIP: I think of tapping a tin can (Tinnel’s) to remember the difference between Phalen’s and Tinnel’s test.

Question 7

what are the key questions to ask someone with carpal tunnel syndrome?

Answer 7

Do symptoms wake you at night?

Do you have trick movements (e.g., shaking the hand) to improve symptoms?

Is your little finger affected? (Answering yes scores negatively, making carpal tunnel syndrome less likely)

Question 8

what is the primary investigation for establishing a diagnosis of carpal tunnel?

Answer 8

Nerve conduction studies are the primary investigation for establishing the diagnosis.

Question 9

what are the management options for carpal tunnel syndrome?

Answer 9

Rest and altered activities

Wrist splints that maintain a neutral

position of the wrist can be worn at night (for a minimum of 4 weeks)

Steroid injections

Surgery