Anatomy of the Hand

Question 1

What are the 7 layers of the palm?

Answer 1

• skin
  
  • palmar aponeurosis
  • thenar and hypothenar muscles
  • neurovascular plane
  • long flexor tendons and lumbricals
  • adductor pollicis and neurovascular plane
  • interossei

Question 2

Why is the palmar aponeurosis difficult to perform surgery on?

Answer 2

because it is connected to the skin

Question 3

Where is the palmar aponeurosis?

Answer 3

extends from the distal border of the flexor retinaculum then divides into 4 parts which insert into skin creases at the base of each finger, the flexor sheaths and the base of the proximal phalanges - does not cover the thenar or hypothenar eminences

Question 4

What is dupuytren’s contracture?

Answer 4

thickening and scarring of palmar aponeurosis forcing a fixed flexion - seen in diabetics, alcoholics and manual workers

Question 5

In what plane is abduction and adduction of the thumb?

Answer 5

right angles to the palm

Question 6

In what plane is extension and flexion of the thumb?

Answer 6

in the same plane as the palm

Question 7

What are the three muscles that make up the thenar eminence?

Answer 7

abductor pollicis brevis, flexor pollicis brevis, opponens pollicis

Question 8

What are the three muscles that make up the hypothenar eminence?

Answer 8

abductor digiti minimi, flexor digiti minimi, opponens digiti minimi

Question 9

What is the relationship of the three muscles in the thenar and hypothenar eminences?

Answer 9

abductors are on the outside, flexors on the inside and opponents are deep

Question 10

What is the origin of the muscles of the thenar and hypothenar eminence?

Answer 10

the flexor retinaculum and adjacent carpal bone

Question 11

What is the insertion of the abducters and flexors of the thenar and hypothenar eminence?

Answer 11

proximal phalynx

Question 12

What is the insertion of the opponens of the thenar and hypotnear eminence?

Answer 12

metacarpals

Question 13

What nerves and vessels are in the superficial neurovascular plane?

Answer 13

superficial palmar arch and the cutaneous nerve supply of the fingers

Question 14

At what heigh is the superficial palmar arch?

Answer 14

at the level of the distal border of the outstretched thumb

Question 15

Where do the fibrous sheaths covering the long flexor tendons extend from?

Answer 15

from the metacarpal heads to the distal phalanges

Question 16

Where do the synovial sheaths covering the long flexor tendons extend from?

Answer 16

from the proximal wrist to the tips of the fingers but with a bare area over the palm (little finger doesn’t have a bare area)

Question 17

Where do the lumbricals originate from?

Answer 17

from the long flexor tendons - lumbrical of 5th finger has to go through the synovial membrane

Question 18

How many lumbricals are there?

Answer 18

4 - one for each of the long flexor tendons

Question 19

How many bodies do the lumbricals have?

Answer 19

1st and 2nd have one body, 3rd and 4th have two bodies

Question 20

Where to the lumbricals insert?

Answer 20

the dorsal extensor expansion on the radial side

Question 21

What is the action of lumbricals?

Answer 21

flex the metacarpophalangeal joints and extend the interphalangeal joints

Question 22

What is the deepest muscle in the hand?

Answer 22

adductor pollicis

Question 23

What is the action of palmar interossei?

Answer 23

adduction

Question 24

What is the action of dorsal interossei?

Answer 24

abduction

Question 25

How many palmar interossei are there?

Answer 25

3 - one for the 2nd, 4th and 5th finger

Question 26

What is the insertion of palmar interossei?

Answer 26

extensor expansion - helps with lumbricals

Question 27

How many dorsal interossei are there?

Answer 27

4 - one on either side of the middle finger and one for the 2nd finger and one for the 4th finger - each has 2 bellies