The Hand

Question 1

Explain how you would test the function of the radial nerve.

Answer 1

Place your hand behind the back of the other person’s hand and ask them to push against it. This tests extension at the wrist.

Question 2

What does an inability to flex the thumb and make the OK sign indicate?

Answer 2

Median nerve injury

Question 3

How would you test for ulnar nerve function?

Answer 3

Ask the patient to make a fist and place ruler under their thumb. If they are unable to sit their thumb out straight on the ruler then this indicates inability to extend the thumb - ulnar nerve injury

Question 4

What is the hand of benediction?

Answer 4

This is seen in patients with median nerve injury when they try to make a fist. They are unable to flex their first two digits.

Question 5

When does ulnar claw present?

Answer 5

This occurs when a patient has their hand in a fist and tries to open it. They are unable to extend the two smallest digits causing ulnar claw.

Question 6

What nerve is affected in carpal tunnel syndrome?

Answer 6

The median nerve

Question 7

What condition leads to inability to oppose the thumb, and emaciation of the thenar muscles?

Answer 7

Carpal tunnel syndrome

Question 8

How can carpal tunnel syndrome be treated surgically?

Answer 8

Release of the flexor retinaculum.

Question 9

What is the thenar eminence?

Answer 9

This is a group of muscles found on the lateral surface of the palm, responsible for opposition of the thumb.

Question 10

Name the muscles found within the thenar eminence.

Answer 10

Abductor pollicis brevis, opponens pollicis, flexor pollicis brevis and adductor pollicis brevis

Question 11

Where does abductor pollicis brevis attach and insert?

Answer 11

This muscle starts at the tubercles of scaphoid and trapezium and also attaches to the flexor retinaculum. It attaches to the lateral side of the base of the proximal phalanx.

Question 12

Where does flexor pollicis brevis attach?

Answer 12

It attaches to the distal phalanx, and originates at the flexor retinaculum and tubercles of scaphoid and trapezium.

Question 13

Describe the difference in function of the superficial and deep heads of flexor pollicis brevis.

Answer 13

The superficial head is responsible for flexion of the thumb and is innervated by the median but the deep head is innervated by the ulnar and is responsible for Adduction of the thumb.

Question 14

Where on the thumb does adductor pollicis attach?

Answer 14

It attaches to the medial side of the base of the proximal phalanx.

Question 15

Name the two heads of adductor pollicis.

Answer 15

Transverse head which attaches to the anterior surface of the third metacarpal and the oblique head which attaches to the base of metacarpals 2/3, capitate and the adjacent carpals.

Question 16

Where is opponens pollicis found?

Answer 16

It is found under abductor pollicis brevis and also attaches to scaphoid, trapezium and the flexor retinaculum. Distally it attaches to the lateral side of the first metacarpal.

Question 17

What functions does palmaris brevis have?

Answer 17

This hollows the palm of the hand aiding grip and also protects the ulnar nerve and artery.

Question 18

Name the muscles of the hypothenar eminence

Answer 18

Opponens digiti minimi, abductor digiti minimi, flexor digiti minimi.

Question 19

Where does abductor digiti minimi attach?

Answer 19

It attaches to pisiform and then the medial side of the base of the proximal phalange.

Question 20

Name two muscles which originate from the hook of hamate and the flexor retinaculum.

Answer 20

Opponens pollicis and flexor digiti minimi brevis

Question 21

Where does opponens pollicis attach?

Answer 21

The medial border of the 5th metacarpal.

Question 22

Where does flexor digiti minimi attach?

Answer 22

It attaches to the medial side of the proximal phalange

Question 23

What nerve supplies the muscles of the hand?

Answer 23

The ulnar nerve supplies all the muscles of the hand except the first two lubricants, opponens pollicis, adductor pollicis brevis and flexor pollicis brevis (superficial head)

Question 24

What is the allens test? When is it used clinically?

Answer 24

This is used to test perfusion to the hand. Both the radial and ulnar arteries are compressed at the hand and then released one at a time and the hand should become red again as it reperfuses. This is done to check that blood supply from the ulnar artery is sufficient before an ABG is taken from the radial artery.

Question 25

How does the ulnar artery divide in the hand?

Answer 25

It splits into the superficial palmar arch and the deep palmar branch.

Question 26

What structures form the deep palmar arch in the hand?

Answer 26

The deep branch of the ulnar artery and anastomoses from the radial artery.

Question 27

What functions do the Lumbricals perform?

Answer 27

These perform flexion of the metacarpophalangeal joints and extension of the interphalangeal joints.

Question 28

Where do the Lumbricals attach?

Answer 28

They all attach to the lateral side of extensor expansions on digits 2-5. They also attach to the tendons of flexor digitorum profoundus.

Question 29

What differences are observed between Lumbricals 1&2 and 3&4?

Answer 29

1&2 are both uni pennate muscles innervated by the median nerve whilst 3&4 are bipennate muscles innervated by the ulnar nerve.

Question 30

What action do palmar interossei perform?

Answer 30

These muscles are responsible for Adduction of the digits and also assist the Lumbricals.

Question 31

Where do the palmar interossei attach?

Answer 31

Attach to the palmar surface of the 2,4,5 metacarpals and then the base of the proximal phalanges and the extensor expansions of digits 2,4,5.

Question 32

What muscles are responsible for abduction of the digits of the hand?

Answer 32

Dorsal interossei.

Question 33

Where do the dorsal interossei attach?

Answer 33

They attach to the base of the proximal phalange and extensor expansion of digits 2,4,5 and then the adjacent metacarpal.

Question 34

How many dorsal interossei muscles are there?

Answer 34

4

Question 35

What is the palmar aponeurosis?

Answer 35

This is a thick fascia which is found between the thenar and hypothenar regions in the centre of the hand and protects the underlying structures such as the long tendons, palmar arch etc. etc.

Question 36

What are the attachments of the flexor retinaculum?

Answer 36

On the medial side it attaches to pisiform and the hook of hamate and on the lateral side it attaches to scaphoid and the ridge of trapezium.