Hand

Question 0

Where is the palmar fascia thin and thick? What does it form in the thick part?

Answer 0

Thin over the thenar and hypothenar eminences. Thick centrally, where it forms the palmar aponeurosis.

Question 1

What number is the thumb and little finger?

Answer 1

Thumb- digit 1

Little finger- digit 5

Question 2

What is the digital sheath, describe its structure, and what structures does it enclose?

Answer 2

Continuation of the palmar aponeurosis. They are ligamentous tubes. Have 5 annular and 4 cruciform sections. Enclose the synovial sheaths and superficial and deep flexor tendons.

Question 3

What does the synovial sheath surround and what is its function?

Answer 3

Surrounds each tendon, both in the digits and in the palm. It produce synovial fluid that lubricates the tendon and prevents friction on movement.

Question 4

Describe the relationship between the synovial sheath and the digital sheath.

Answer 4

Synovial sheath is deeper, and the fibrous digital sheath wraps around it.

Question 5

Name the muscles in the thenar eminence.

Answer 5

Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis

Question 6

Name the hypothenar muscles.

Answer 6

Abductor digiti minimi
Flexor digiti minimi brevis
Opponens digit minimi.

Question 7

What nerve innervates the thenar muscles?

Answer 7

Median nerve.

Question 8

What nerve innervates the hypothenar muscles?

Answer 8

Ulnar nerve.

Question 9

Name the muscle that adducts the thumb and is in its own separate compartment?

Answer 9

Adductor pollicis.

Question 10

Where does palmaris brevis originate and insert? What does it overlie and what is its function?

Answer 10

Originates from flexor retinaculum and inserts into dermis. Overlies the hypothenar muscles. Action is to tense the ulnar side of the palm and makes the palm hollow for gripping. It also covers and protects the ulna artery.

Question 11

What is the function of the lumbricles?

Answer 11

Flex the fingers at the metacarpalphalangeal joints and extend the interphalangral joints.

Question 12

Which way round are the 4 lumbricles named?

Answer 12

1-4 is medial-lateral.

Question 13

Where do the lumbricles originate and insert?

Answer 13

Originate at the tendons of flexor digitorum profoundus and insert at extensor portions, so don’t attach to bone.

Question 14

How many interossei muscles are there?

Answer 14

4 dorsal, 3 palmar.

Question 15

What action do the lumbricles cause?

Answer 15

Palmar lumbricles adducts, dorsal lumbricles abduct. PAD DAB.
Acting together the lumbricles flex the MCP joint and extend the IP joint.

Question 16

How do you test the interossei muscles?

Answer 16

Adduction- patient holds paper between fingers, tester should no be able to remove it.
Abduction- patient tries to abduct fingers against tester providing resistance.

Question 17

What nerve(s) supply the lumbricles?

Answer 17

1 & 2 is supplied by median nerve.

3 & 4 is supplied by ulnar nerve.

Question 18

What nerve(s) supplies the interossei muscles?

Answer 18

Both palmar and dorsal are supplied by ulnar nerves.

Question 19

Why is a good blood supply to the hand important?

Answer 19

Hand has a high function, so need a good supply of oxygen and nutrients to the intrinsic muscles.

Question 20

What is the arterial supply to the hand comprised off?

Answer 20

Ulnar and radial arteries, and their branches.

Question 21

Talk about the ulna arterial supply to the hand.

Answer 21

Ulna artery enters the hand anterior to flexor retinaculum via the ulnar canal/guyon canal. It then divides into the superficial and deep palmar artery. These then anastomoses with the radial arteries. Gives off further branches from Palmer arch, into a pair of proper palmar digital arteries.

Question 22

Where does the ulna artery and radial artery supply?

Answer 22

Ulna supplies 3.5 fingers, little to middle. Radial does the rest.

Question 23

Talk about the venous drainage of the hand.

Answer 23

Superficial and deep venous Palmer arches drain into the forearm veins. On the back of the hand you have dorsal venous network. These veins are used for canulas.

Question 24

What nerves supply the hand?

Answer 24

Median, radial and ulna.

Question 25

How does the median nerve enter the hand, and what does it supply?

Answer 25

Enters through the carpal tunnel. Supplies the thenar muscles (loaf):
Lumbricles 1 and 2, Opponens pollicis, abductor pollicis brevis and flexor pollicis brevis.
Palmar cutaneous branch supplies palm. Also supplies lateral 3.5 digits palmar side and finger tips dorsal side.

Question 26

How does the ulna artery enter the hand?

Answer 26

Via Guyon canal with ulna artery. It’s superficial to flexor retinaculum.

Question 27

What muscles does the ulna nerve supply?

Answer 27

Lumbricles 3 and 4, Opponens digiti minimi, abductor digit minimi, flexor digiti minimi and interossei.
Supplies medial 1.5 digits on front and back of hand.

Question 28

What does the radial nerve supply in the hand?

Answer 28

Only supplies skin, no intrinsic muscles. Hit does supply the extensor muscles in the forearm though.

Question 29

What are the boundaries of the carpal tunnel?

Answer 29

Floor- U shaped carpal bones
Roof- flexor retinaculum
Medial- pisiform and hook of hamate
Lateral- tubercle of scaphoid and trapezium

Question 30

What is the content of the carpal tunnel?

Answer 30

9 tendons; 4 flexor digitorum superficialis, 4 flexor digitorum profoundus and 1 flexor pollicis longus.
Median nerve.