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Flashcards in "The Hand" Questions Deck (75)
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1

What are the names of the 5 fingers?

Thumb
Index
Middle
Ring
Little
- don't number them

2

What is the palmar fascia, where is it, and what does it form?

Fascia of the hand that lies in the palm
- forms specialisations = palmar aponeurosis and fibrous digital sheaths

3

What is the palmar aponeurosis, what does it overlie and what structures is it continuous with?

Specialisation of palmar fascia
- overlies the long flexor tendons (hand)
- continuous with flexor retinaculum + palmaris longus tendon proximally
- continuous with fibrous digital sheaths

4

What are the fibrous digital sheaths?

Tubes which contain the flexor tendons and their synovial sheaths

5

How are the compartments of the hand divided up and what are the compartments?

Space between palmar aponeurosis and bones of the hand are separated by extensions of fascia (aka septa)
- hypothenar
- central (midpalm)
- thenar
- adductor
- interosseous
(viewed through cross-section of the hand distal to the wrist, (moving from medial to lateral) hypothenar, central, thenar, adductor (just below thenar), interosseous (bottom of the palm))

6

What are the 3 grips the hand is capable of?

Power
Precision
Hook

7

What is the neuromuscular basis of the power grip?

Fingers are pressed against palm with counter pressure from the thumb (e.g. grasping a rod)
Muscles needed:
- long flexors of fingers/thumb
- intrinsic muscles of the palm
- extensors of the wrist joint

8

What is the neuromuscular basis for the precision grip?

Wrist and fingers held rigidly, intrinsic muscles of the hand carry out fine movements needed (e.g. unbuttoning a shirt)
Muscles needed:
- long flexors/extensors of wrist/thumb/fingers (hold joints rigid)
- intrinsic muscles of the hand (fine movements)

9

What is the neuromuscular basis for the hook grip?

Consumes little energy, mainly involves long flexors of the digits (e.g. carrying shopping bag/briefcase)
Muscles needed:
- long flexors of the digits

10

What are the bones involved in the wrist and hand?

Radius
Ulna
Carpal bones
Metacarpal bones
Phalanges

11

What are the carpal bones and the mnemonic to remember them?

So Long To Pinky
Here Comes The Thumb
- Scaphoid
- Lunate
- Triquetrum
- Pisiform (sesamoid bone)
- Hamate
- Capitate
- Trapezoid
- Trapezium

12

What bones does the radius articulate with in the wrist?

Proximal row
- scaphoid, lunate, triquetrum

13

How does the ulna interact with the wrist?

Does not itself articulate with any carpal bones.
Articulates with triangular fibrocartilage which extends from the distal radius to the ulna

14

What is unusual about the scaphoid bone and why is this clinically relevant?

Has an unusual blood supply where the vessels pass from distal to proximal (back to front)
- clinically relevant as fracture of the waist of the scaphoid bone can damage/cut off this blood supply causing avascular necrosis

15

What are the features of the metacarpal bones and how many are there?

Body (shaft), base (proximal), head (distal)
- 5, numbered 1 to 5 (1 = thumb, 5 = little finger)

16

What are the features of the phalanges, how many are there in each finger and what are each phalanx called?

Body (shaft), base (proximal), head (distal)
- 3 in each finger, 2 in the thumb
- proximal, middle, distal (thumb does not have a middle phalanx)

17

What are the 4 compartments of the intrinsic hand muscles?

Hypothenar
Interossei + lumbricals
Thenar
Adductor

18

What muscles are in the hypothenar compartment of the hand?

Abductor digiti minimi
Flexor digiti minimi
Opponens digiti minimi

19

What muscles are in the interossei + lumbricals compartment of the hand?

Lumbricals (4 muscles)
Palmar interossei
Dorsal interossei

20

What muscles are in the thenar compartment of the hand?

Abductor pollicis brevis
Flexor pollicis brevis
Opponens pollicis

21

What muscles are in the adductor compartment of the hand?

Adductor pollicis

22

What is the outlier muscle that is part of the intrinsic muscles of the hand and what does it do?

Palmaris brevis
- improves grip

Innervated by superficial branch of the ulnar nerve

23

What are the actions of the muscles of the hypothenar compartment and what nerve innervates these muscles?

Abductor digiti minimi - abducts little finger at MCP joint
Flexor digiti minimi - flexes little finger at MCP joint
Opponens digiti minimi - laterally rotates metacarpal 5 (allows opposition of little finger with thumb)

All supplied by the deep branch of the ulnar nerve

24

What are the actions of the muscles of the interossei + lumbricals compartment of the hand and what nerve innervates these muscles?

Lumbricals - flex MCP joints while extending IP joints (straight fingers)
Palmar interossei - adduction of thumb, index, ring, and little fingers at MCP joints
Dorsal interossei - abduction of thumb, index, ring, and little fingers at the MCP joints

Lumbricals divided into 2+2, lateral 2 by deep branch of the ulnar nerve, medial 2 by digital branches of median nerve

25

What are the actions of the muscles of the thenar compartment of the hand and what nerve innervates these muscles?

Abductor pollicis brevis - abducts thumb at MCP joint
Flexor pollicis brevis - flexes thumb at MCP joint
Opponens pollici - medially rotates thumb (allows opposition with little finger)

All supplied by the recurrent branch of the median nerve

26

What are the actions of the muscles of the adductor compartment of the hand and what nerve innervates these muscles?

Adductor pollicis - adducts the thumb

Supplied by deep branch of the ulnar nerve (all other thumb muscles are recurrent branch of median but adductor is NOT)

27

What two spinal roots are being tested in the test of any of the intrinsic muscles of the hand?

C8 and T1 (roots for literally all the muscles)

28

What are the fibrous digital sheaths and where do they extend?

The fibrous digital sheaths are condensations or specialisations of the palmar fascia
- they extend from the level of the metacarpal head to the base of the distal phalanx in each digit (so the whole finger basically)

29

What do the fibrous digital sheaths form with the underlying bone and what runs through these?

Form OSSEO-FIBROUS TUNNELS through which the long flexor tendons and their synovial sheaths run

30

What do parts of the fibrous digital sheaths form and what is the function of these structures?

Further condensations called PULLEYS
- allow for more functional use of the long flexor tendons
Annular and Cruciform pulleys

31

How are the synovial sheaths of the FDP/FDS tendons organised in the hand?

Tendons of FDP/FDS pass deep to the flexor retinaculum and enter a common synovial sheath
Tendons then pass to their respective digit via a digital synovial sheath, contained within the fibrous digital sheath
The exception is FPL which has its own synovial sheath at the level of the flexor retinaculum
The digital synovial sheaths of the index, middle, and ring fingers are separate from the common synovial sheath while the digital synovial sheaths of the little finger and thumb are continuous with the common synovial sheath.

32

Where do the flexor digitorum profundus/superficialis and flexor pollicis longus tendons attach?

FDP - distal phalanx
FDS - middle phalanx
FPL - distal phalanx of the thumb
(all anterior surfaces given that they need to be flexing these digits)

33

What holds all the extensor tendons to the back of the wrist?

Extensor retinaculum

34

What happens to the long extensor tendons at the level of the metacarpals and what attaches here?

Long extensor tendons flatten out and form extensor expansions - form a hood on the back of each digit
- lumbrical and interessei attach to these extensor expansions
- these expansions are intricately involved in the movements of the digits

35

In general throughout the hand, what do the digit flexor/entensor tendons have surrounding them and what surrounds those?

Digital synovial sheaths
- enclosed in the fibrous digital sheaths

36

What are the joints of the region of the hand + wrist?

Distal radio-ulnar joint
Wrist joint
Intercarpal joint
Carpometacarpal joints
Intermetacarpal joints
Metacarpo-phalangeal joints
Interphalangeal joints

37

What type of joint is the distal radio-ulnar joint, what movement does it allow, and what is commonly injured within it?

Pivot-type joint
- allows radius to move around ulna in rotation of forearm
- triangular fibrocartilage (an articular disc) is commonly injured

38

What type of joint is the wrist joint, what is it formed between and what is commonly injured within it?

Synovial joint
- formed between distal radius + its associated triangular fibrocartilage and the proximal row of carpal bones (not pisiform tho)
- radio-carpal and inter-carpal ligaments frequently injured

39

What type of joints are the intercarpal joints and which bones are they formed between?

Synovial
- joints between proximal row of carpal bones
- joints between distal row of carpal bones
- joints between the two rows are called "mid-carpal' joints

40

Where are the carpometacarpal joints found and which one is clinically important?

Carpometacarpal (CMC) joints are formed between the distal row of carpal bones and the metacarpals.
The CMC joint of the thumb is between the trapezium and thumb metacarpal, and the digit CMC joints are between the trapezoid, capitate and hamate bones and the metacarpals at each point.
- clinically speaking, the thumb CMC often becomes osteoarthritic, (it is a synovial joint of the saddle variety)

41

Where are inter-metacarpal joints formed?

Between the BASES (proximal ends) of the metacarpal bones

42

What kind of joints are the metacarpo-phalangeal joints and where are they formed?

CONDYLAR synovial joints
- formed between metacarpal heads (distal ends) and the proximal phalanges

43

What kind of joints are the inter-phalangeal joints and where are they formed?

HINGE synovial joints
- formed between the different phalanges (so 2 IP joints in each finger, 1 in the thumb)

44

What is an important structure in the finger that is frequently damaged and where is it?

Volar plate
- important structure on the anterior surface of the proximal IP joint
- dense condensation of fibrous tissue formed by the collateral ligaments and frequently damaged

45

What makes up the arterial supply of the hand?

Hand is supplied by the ulnar and radial arteries with extensive anastomoses between the two once in the hand

46

How does the ulnar artery enter the hand?

Runs into the hand over the flexor retinaculum, lateral to the pisiform in Guyon's canal (with ulnar nerve, lateral to it)

47

What are the divisions of the ulnar artery once it has entered the hand?

Superficial palmar arch
Deep palmar branch of the ulnar artery

(Superficial arch gives off 3 common palmar digital arteries which subsequently divide into palmar digital arteries)

48

How does the radial artery enter the hand?

Crosses the floor of the anatomical snuff box and enters the palm of the hand between the two heads of the first dorsal interosseous muscles

49

What arteries are formed from the radial artery in the hand?

Radial artery anastomoses with deep palmar branch of ulnar artery to form the deep palmar arch
- deep palmar arch then gives rise to the palmar metacarpal arteries

50

How is venous drainage within the hand organised?

The superficial and deep palmar arterial arches have corresponding palmar venous arches.
- the dorsal digital veins drain into the dorsal venous arch on the back of the hand which forms the cephalic vein laterally and the basilic vein medially
(- most of the venous drainage of the hand is by the superficial system but some is via the deep system)

51

What is the role of the brachial plexus? (just the principle of what is is/does)

Responsible for the cutaneous (sensory) and muscular (motor) innervation of the entire upper limb except the trapezius (spinal accessory nerve), and an area of skin near the axilla (intercostobrachial nerve).

52

Where is the median nerve located when it enters the wrist and what muscles does it supply in the hand?

Lies superficially between the tendons of FDS/FDP and deep to palmaris longus before entering the carpal tunnel
- motor supply to the 3 thenar muscles (recurrent branch of the median nerve)
- motor supply to the lateral (1st/2nd fingers) lumbricals (as median nerve)

53

What parts of the hand is the median nerve the sensory supply of?

Palmar surface of the thumb, index, middle fingers, and lateral half of the ring finger
Some of the dorsal surface of these digits

54

Which nerves supply the flexor digitorum profundus and superficialis muscles?

FDS (all branches) = median nerve
FDP (half and half) = little and ring fingers are ulnar (dorsal cutaneous branch), index and middle fingers are median

55

When and into what, does the ulnar nerve divide approaching the wrist?

Divides before and after entering the hand
Proximal to the wrist, divides into palmar and dorsal cutaneous branches
Distal to the wrist, it divides into the superficial and deep branch of the ulnar nerve.

56

What do the different branches of the ulnar nerve in the wrist supply?

- Pre-wrist divisions
Palmar cutaneous - medial palm
Dorsal cutaneous - medial half of dorsum of the hand, ring/little fingers
- Post-wrist divisions
Superficial - sensory supply to palmar surface of little finger and medial side of ring finger
Deep - motor supply to hypothenar muscles, adductor pollicis, medial lumbricals, all the interossei

57

What does the radial nerve divide into?

Superficial radial nerve (sensory)
Posterior interosseous nerve (motor)

58

What does the superficial branch of the radial nerve supply?

Sensory to lateral 2/3rds of dorsum of the hand, dorsum of the thumb, and bases of dorsum of index/middle fingers

59

What does the deep branch (posterior interosseous nerve) of the radial nerve supply?

NO supply to hand
- supplies all extensor muscles in the forearm

60

What are the borders of the carpal tunnel?

Base - bony arch of the carpal bones
Roof - flexor retinaculum
Medially - hook of the hamate, pisiform bones
Laterally - tubercle of the scaphoid, ridge of the trapezoid bone

61

What are the contents of the carpal tunnel?

Median nerve
FPL tendon
4 tendons of FDP
4 tendons of FDS

62

What is carpal tunnel syndrome?

An entrapment syndrome caused by pressure on the median nerve within the carpal tunnel

63

What can cause carpal tunnel syndrome?

Swelling of tendons in the carpal tunnel
Formation of cysts in the carpal joints or tunnel

64

What are the results of carpal tunnel syndrome? (signs/symptoms)

Pain or pins and needles in distribution of the median nerve in the hand, usually with preservation of the palm (palmar cutaneous branch of median nerve comes off a few centimetres above the carpal tunnel)
May also be weakness or loss of muscle bulk on the thenar muscles

65

What is Timel's sign and what is it used for?

A test for carpal tunnel syndrome (CPS)
- gently tapping over the median nerve in the region of the flexor retinaculum readily produces the symptoms of CPS (positive sign)

66

Where can the ulnar nerve be easily injured?

Near the elbow (passes posteriorly to medial epicondyle)

67

Where can the radial nerve be easily injured?

Radial groove along the shaft of the humerus (in shaft fracture)

68

What happens when there is a lesion in the brachial plexus to C8 and T1?

Klumpke's paralysis
- presents as a claw hand, paralysis of intrinsic hand muscles and ulnar nerve cutaneous distribution numbness.
- mainly affects intrinsic muscles of the hand and flexors of the wrist/fingers

69

What are the main 5 creases of the palm?

Distal to proximal
- palmar digital creases (base of each finger)
- distal palmar (transverse) crease (marks position of MCP joints
- proximal palmar (transverse) crease
- radial longitudinal crease
- wrist crease

70

How would one test the flexor pollicis longus?

Hold the proximal phalanx of the thumb and ask subject to flex distal phalanx of the thumb against resistance
- remember to stabilise the interphalangeal joint

71

How would one test the extensor pollicis longus?

Ask subject to extend the thumb against resistance at the IP joint
- tendon should become visible

72

How would one test the flexor digitorum profundus?

Hold the proximal IP joint in extension and ask subject to flex distal IP joint against resistance

73

How would one test the flexor digitorum superficialis?

Each digit should be tested separately
Hold other fingers in extension and ask subject to flex proximal IP joint against resistance
- stabilise the MCP joint below it as well

74

How would one test the extensor digitorum?

Pronate subject's forearm and ask for them to extend their fingers normally.
Apply resistance on the proximal phalanges and ask them to resist you
- tendons should become visible at base of dorsum of hand

75

How would one test the dorsal and palmar interossei?

Remember PAD, DAB
- Dorsal - ask patient to extend two adjacent fingers and keep them together. Then apply resistance on the outside of each and ask subject to move those fingers apart
- Palmar - ask subject to hold a slip of paper between two extended fingers, ask subject to try and close the fingers tightly on the paper and stop you from removing the paper