Session 4-Functional Anatomy Of The Hand

Question 1

Describe how the Allen Test is carried out

Answer 1

Patient squeezes hand tightly and examiner places thumb and index finger over radial and ulnar arteries, compressing them. Patient opens hand while pressure is maintained, one artery tested by releasing pressure over that artery to see if hand flushes, same done to other artery and comparison is made

Question 2

Why is the Allen test carried out?

Answer 2

50% of people don’t have an ulnar artery so this test is done to check before a blood gas is done because if a patient only has radial artery, blood gas could jeopardise circulation

Question 3

Why is arterial blood gas used?

Answer 3

To sample arterial blood to measure O2 concentration, CO2 concentration, pH etc - can be life saving if breathing and circulation is compromised

Question 4

What are the functions of palmar skin? (3)

Answer 4

Grasping
Feeling
Moving underlying joints

Question 5

What does the nail arise from and what happens if this is damaged?

Answer 5

From germinal matrix (small semi-circle at base of nail)

If damaged, no nail will grow

Question 6

True or false: thick skin has many densely compacted layers and the epidermis indents into the dermis, allowing the skin to move

Answer 6

TRUE

Question 7

Which digits does the median nerve supply?

Answer 7

Radial 3 1/2 digits: thumb, index and middle fingers and half of the ring finger

Question 8

True or false: median nerve is deep to the flexor tendons

Answer 8

FALSE - superficial

Question 9

True or false: the median nerve enters the hand through the carpal tunnel

Answer 9

TRUE

Question 10

Which four carpal bones form the borders of the carpal tunnel?

Answer 10

Trapezium
Scaphoid
Pisiform
Hamate

Question 11

Which three muscles make up the thenar eminence?

Answer 11

Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis

Question 12

Which mnemonic is used to remember which four muscles of the hand are supplied by the median nerve?

Answer 12

LOAF

Question 13

Which four muscles of the hand are supplied by the median nerve?

Answer 13

Lateral two lumbricals
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis

Question 14

Which canal does the ulnar nerve pass through?

Answer 14

Guyon’s canal

Question 15

Which digits does the ulnar nerve supply?

Answer 15

Little finger and half of ring finger

Question 16

True or false: the ulnar nerve is superficial to the long flexor tendons

Answer 16

FALSE - deep

Question 17

Which muscles does the ulnar nerve supply?

Answer 17

Interossei

Question 18

True or false: the radial nerve doesn’t supply any muscles in the palm of the hand

Answer 18

TRUE - supplies forearm and back of hand

Question 19

How many flexor tendons does each digit have?

Answer 19

Two flexor tendons per finger and one long flexor tendon for the thumb

Question 20

Where does flexor digitorum profundus attach?

Answer 20

To distal phalanx

Question 21

Where does flexor digitorum superficialis attach?

Answer 21

To middle phalanx

Question 22

True or false: no blood supply runs along the tendons, the blood supply runs on the underlying bone instead

Answer 22

TRUE

Question 23

True or false: dorsiflexion of wrist increases finger grip strength

Answer 23

TRUE

Question 24

What are the extensor tendons of the fingers called?

Answer 24

Extensor digitorum communis

Question 25

What is the long tendon in the thumb called?

Answer 25

Extensor pollicis longus

Question 26

What are the lumbricals?

Answer 26

Muscles arising from flexor tendons that allow MCP joint to flex and extends the IP joints

Question 27

True or false: the index and little fingers have an extra tendon with extra muscle so they can be lifted independently

Answer 27

TRUE

Question 28

What is the flexor retinaculum?

Answer 28

Fibrous band on palmar side of hand near the wrist, arches over carpal bones of the hand and forms the carpal tunnel

Question 29

What are the bony attachments of the flexor retinaculum?

Answer 29

Pisiform
Hamate
Scaphoid
Trapezium

Question 30

Which structures pass through the carpal tunnel?

Answer 30

Median nerve

Nine tendons: flexor pollicis longus, four flexor digitorum superficialis and four flexor digitorum profundus