Hand

Question 1

What are the four types of joints in the hand?

Answer 1

Carpometacarpal joint

Metacarpal phalangeal joint

proximal interphalangeal joint

Distal interphalangeal joint

Question 2

Which digit only has 2 phalanges?

Answer 2

Thumb (1st digit)

Question 3

What is the most commonly fractured carpal bone?

Answer 3

scaphoid

Question 4

where does a scaphoid commonly fracture?

Answer 4

along the long axis

Question 5

Describe the 1st carpmetacarpal joint

Answer 5

synovial joint - saddle type

wide range of movements here including flexion, extension, abduction, adduction, opposition -

this joint is involved in the Bennet’s fracture

Question 6

What muscles compose the long flexors of the finger?

Answer 6

Flexor digitorum profundus

Flexor digitorum superficialis

*both median nerve*

Question 7

What joints does flexor digitorum profundus act on?

Answer 7

EVERY joint in the hand!

Question 8

What are the Thenar muscles?

Answer 8

OAF

O= opponens pollicis

A= abductor pollicis brevis

F= flexor pollicis brevis

Question 9

What are the two heads of adductor pollicis called?

Answer 9

• Transverse head of adductor pollicis
• Oblique head of adductor pollicis

Question 10

What is the nerve supply to the thenar muscles?

Answer 10

Remember thenar muscles = opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis - nerve suppy = median nerve

Deep to these thenar muscles is adductor pollicis whos nerve supply is the ulnar nerve!

Question 11

What are the hypothenar muscles? What is their nerve supply?

Answer 11

Abductor digiti minimi

flexor digiti minimi

opponens digiti minimi

(ulnar nerve)

Question 12

What are the roots of the ulnar nerve?

Answer 12

C8 and T1

Question 14

What tendon do the lumbricals arise from?

Answer 14

They arise from the flexor digitorum profundus tendons

Question 15

What is the function of the lumbricals?

What are their innervations?

Answer 15

flex the metacarpal phalangeal joint and extend the interphalangeal joints

innervated by median nerve on radial side

innervated by ulnar nerve on ulnar side

Question 16

What are the inerossei muscles? What action are they responsible for? What is their nerve supply?

Answer 16

They are responsible for the adduction/abduction of your fingers

you have dorsal interossei and palmar interossei (PAD and DAB)

nerve supply = ulnar nerve (C8 T1)

Question 17

What lies under the carpal tunnel?

Answer 17

Flexor digitorum superficialis

flexor digitorum profundus

median nerve

flexor pollicis longus tendon

Question 18

What structures pass over the flexor retinaculum?

Answer 18

ulnar artery

ulnar nerve

palmar cutaneous branch of ulnar nerve

tendon of palmaris longus

palmar cutaneous branch of median nerve

Question 19

What are the clinical symptoms of carpal tunnel syndrome?

Answer 19

tingling/numbness of the first 3 and half digits -

wasting of the thenar eminence due to inability of OAF

opponens pollicis, abductor pollicis brevis, flexor pollicis brevis

Question 20

What is the purpose of the finger synovial sheath?

what are the implications?

Answer 20

the synovial sheaths reduce friction in your fingers - but they can also spread infection

Question 21

what structure overlies the long flexor tendons in the palm?

Answer 21

the palmar aponeurosis

Question 22

Where does the palmar aponeurosis spred from?

Answer 22

it spreads from the flexor retinaculum and the palmaris longus tendon to the bases of the proximal phalances

Question 23

With is Dupuytren’s contracture?

Answer 23

common problem that results in fibrosis of the palmar aponeurosis- leading to shortening/thickening of the digital bands that pull the digits (4th and 5th especially) to varying degrees of flexion. Surgery is required to correct this deformity

Question 24

How does the ulnar artery enter the hand?

Answer 24

it ents anterior to the flexor retinaculum between pisiform and hook of hamate (Guyon’s canal)

It divides into superficial and deep branches

it is the man contributor to the superficial arch

Question 25

How does the radial artery enter the hand?

Answer 25

It curves around scaphoid and trapezium, passes between the heads of 1st dorsal interosseous muscle then between heads of adductor pollicis Forms an anastomosis with deep branch of ulnar artery (deep palmar arch)

Question 26

what is the allen's test?

Answer 26

place fingers on the radial artery and ulnar artery in the wrist cutting off blood supply to the hand- then release one of them to test the profusion of the anatomoses. If there is a true anatomosis, one artery should be sufficient to profuse the entire hand

Question 27

Describe the path of the ulnar nerve

Answer 27

After arising from the brachial plexus, the ulnar nerve descends down the medial side of the upper arm. At the elbow, it passes posterior to the medial epicondyle of the humerus, entering the forearm. At the medial epicondyle, the nerve is easily palpable and vulnerable to injury. In the forearm, the ulnar nerve pierces the two heads of the flexor carpi ulnaris, and travels alongside the ulna. Three branches arise in the forearm: Muscular branch: innervates some muscles in the anterior compartment of the forearm. Palmar cutaneous branch: innervates the skin of the medial half of the palm. Dorsal cutaneous branch: innervates the skin of the medial 1 and 1/2 fingers, and the associated palm area.

Question 28

Where does the ulnar nerve give off the dorsal cutaneous nerve?

Answer 28

Aprox. 5cm proximal to the wrist, the dorsal cutaneous nerve passes deep to flexor carpi ulnaris to supply the dorsal aspect of the hand.

Question 29

What muscles are supplied by the ulnar nerve in the hand? flexor carpi ulnaris ulnar half of flexor digitorum profundus hypthenar muscles Interossei 3rd and 4th lumbricals adductor pollicis

Answer 29

Everything but LOAF is supplied by the ulnar nerve in the hand

Question 31

Name the structures at the wrist from lateral to medial

Answer 31

Tendon of brachioradialis radial artery flexor carpi radialis median nerve (palmaris longis superficial to this) Flexor digitorum superficialis ulnar artery ulnary nerve flexor carpi ulnaris

Question 32

What is the tendon that 15% of population doesn't have at the wrist?

Answer 32

palmaris longus

Question 33

Describe the myotomes of the arm

Answer 33

Shoulder extension and abduction = C5 shoulder flexion and adduction = C6,7,8 Elbow flexion = C5,6 Elbow Extension = C7,8 Radioulnar supination/pronation = C6 Fingers flextion/extension = C7,8 Fingers abduction/adduction/small muscles = T1