The Hand

Question 1

Answer 1

Question 2

which muscle of the forearm (not found in everyone) is continuous with the fascia of the palm shown?

Answer 2

palmaris longus

Question 3

working from superficial to deep, there are 5 compartments of the hand:

Answer 3

• thenar compartment
• hypothenar compartment
• lumbricals and long flexor tendons - central compartment
• adductor compartment
• interosseous compartment

Question 4

what do the thenar muscles of the hand form?

Answer 4

the fleshy muscle belly (thenar eminence) on the lateral aspect of the palm

Question 5

Name the three Thenar muscles

short ones

Answer 5

• abductor pollicis brevis (APB)
• flexor pollicis brevis (FPB)
• opponens pollicis (OP) lies immediately deep to the above muscles.

Question 6

label the thenar muscles

Answer 6

Question 7

Answer 7

Question 8

which nerve segment from the brachial plexus serves to provide the majority of the innervation to the thenar muscles?

Answer 8

C6-T1, median nerve,can contain fibres from C5 in some individuals

Question 9

what do the hypothenar muscles form?

Answer 9

the fleshy muscle belly (hypothenar) eminence on the medial aspect of the palm

Question 10

what are the three hypothenar muscles called?

Answer 10

• abductor digiti minimi
• flexor digit minimi
• opponens digiti minimi

Question 11

label the hypothenar muscles

Answer 11

Question 12

which nerve innervates the hypothenar muscles?

Answer 12

ulnar nerve

Question 13

which nerve root from the brachial plexus serves to provide the majority of the innervation to the hypothenar muscles?

Answer 13

C8-T1, ulnar nerve

Question 14

what does opponens mean in relation to muscles?

Answer 14

• contraction of the muscle results in the movement of either the thumb (pollicis), or little finger (digiti minimi) towrads the other fingers

Question 15

lying deep to the thenar and hypothenar eminence is which compartment?

Answer 15

central compartment

Question 16

what does the central compartment of the hand contain?

Answer 16

Flexor tendons passing distally from the forearm to the digits, with their respective synovial sheathes:
- flexor digitorum superficialis
- flexor digitorum profundus
- flexor pollicis longus

Additionally, 4 small muscles of the hand originate here called the Lumbricals.

Question 17

what do the lumbricals arise from?

Answer 17

They arise from the medial and lateral aspects of the FDP tendon, between the 1st to 5th metacarpals.

Question 18

what is the action of the lumbricals?

Answer 18

The lumbricals flex the fingers at the metacarpophalangeal joint and extend the interphalangeal joint of 2nd to 5th digits.

Question 19

what is the innervation of the lumbricals?

Answer 19

• medial two lumbricals are innervated by the ulnar nerve
• lateral two are innervated by the median nerve

Question 20

The adductor pollicis lies deep in the hand below the neurovascular structures and has 2 heads. Label these heads.

Answer 20

Question 21

which nerve innervates adductor pollicis?

Answer 21

ulnar nerve C8-T1

Question 22

describe the Interossei muscles

Answer 22

These muscles are deepest in the hand and lie between the metacarpal bones. There are 4 doarsal and 3 palmar interossei.

Question 23

what is the action of the dorsal interossei muscles?

Answer 23

DAB
Dorsal interossei ABduct the fingers

Question 24

what is the action of the palmar interossei muscles?

Answer 24

PAD
Palmar interossei ADduct the fingers

Question 25

which nerve innervated the dorsal and palmar interossei muscles?

Answer 25

ulnar nerve

Question 26

which spinal segment contributes the most to the innervation of the interossei?

Answer 26

C8-T1, ulnar nerve

Question 27

what is the blood supply to the hand composed of?

Answer 27

The ulnar and radial arteries provide the blood supply to the hand. Once they reach the palm they form the superficial and deep palmar arch.

These arches anastomose with each other, therefore if one artery becomes blocked the other can maintain blood supply via. its collateral circulation.

Question 28

which artery is the main contributor of the superficial palmar arch?

Answer 28

ulnar artery

Question 29

which artery is the main contributor of the deep palmar arch

Answer 29

radial artery

Question 30

Answer 30

Question 31

which nerves supply the muscles of the hand?

Answer 31

median and ulnar nerves

Question 32

Answer 32

Question 33

the ulnar nerve is a branch of which cord of the brachial plexus?

Answer 33

medial cord

Question 34

how would we test the motor and sensory function of the axillary nerve?

Answer 34

motor: abduct the shoulders (deltoid)
sensory: outer aspect of shoulder

Question 35

how would we test the motor and sensory function of the musculocutaneous nerve?

Answer 35

motor: flex the elbow (biceps, brachialis)
sensory: lateral aspect of forearm

Question 36

how would we test the motor and sensory function of the radial nerve?

Answer 36

motor: extend your wrist (posterior compartment of forearm)
sensory: posterior arm, forearm and dorasl aspect of lateral 3 and a half fingers

Question 37

how would we test the motor and sensory function of the ulnar nerve?

Answer 37

motor: spread your fingers (intrinsic muscles of the hand)
sensory: palmar and dorsal aspect of the medial 1 and a half fingers

Question 38

how would we test the motor and sensory function of the median nerve

Answer 38

motor: move youir thumb towards your nose (abductor pollicis brevis)
sensory: palmar aspect of lateral 3 and a half fingers