Movements and muscles of the hand

Question 1

Which digits of the hand does the median nerve supply innervation to?

Answer 1

Palmar aspect of hand: lateral half of the ring finger, middle finger, index finger and thumb, and the palmar area underneath these fingers

Dorsal aspect of hand: tip of thumb and tips of index, middle and ring finger

Question 2

Which areas can be test for purely median nerve sensory loss?

Answer 2

Tip of the index and middle finger

- This is where you would lose sensation on median nerve injury

Question 3

If you injure the median nerve, where would the motor loss be? (Think about which muscle is purely median nerve innervated)

Answer 3

ABductor pollicis brevis - abductor of thumb

• Assess function of this muscle
• Place thumb over middle of palm, place your finger above and ask the patient to touch your finger with their thumb = ABduction = purely median nerve action

Question 4

Which nerve MAINLY supplies the small muscles of the hand

Answer 4

Ulnar nerve

Question 5

Which areas are supplied sensation by the ulnar nerve?

Answer 5

Little finger and medial half of ring finger (palmar and dorsal)

Question 6

Which area can be tested for purely ulnar nerve sensory loss?

Answer 6

Medial half of palm - particularly over the tip of the little finger

Question 7

Which muscles are tested when assessing ulnar nerve motor function? How is this test performed?

Answer 7

The interossei muscles - PAD/DAB

• They are supplied by the ulnar nerve
• Ask patient to hold paper between digits and see how hard they can hold it if we try to pull it out

Question 8

Where does the radial nerve mainly supply motor function?

Answer 8

Extensors of the forearm but NO muscles in the hand

Question 9

Which area can be tested for radial nerve sensation loss? What is the sign of radial nerve damage?

Answer 9

Dorsal aspect of hand, in the webbing of the thumb

- Wrist drop / weakness of wrist extension