S9) The Hand Flashcards Preview

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Flashcards in S9) The Hand Deck (59)
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1
Q

Identify and describe the bones of the wrist and hand

A

- Carpal bones – set of eight irregularly shaped bones located in the wrist area

  • Metacarpals – five bones, each related to a digit
  • Phalanges – each finger has three phalanges (thumb has two)
2
Q

Identify the carpal bones according to their organisation proximally and distally

A
  • Proximal row: scaphoid, lunate, triquetrum, pisiform
  • Distal row: trapezium, trapezoid, capitate, hamate
3
Q

Describe the proximal and distal articulations of the carpal bones

A
  • Proximal: scaphoid and lunate articulate with the radius
  • Distal: carpal bones articulate with the metacarpals
4
Q

Describe the arrangement of the metacarpal bones

A
  • Metacarpal I – thumb
  • Metacarpal II – index finger
  • Metacarpal III – middle finger
  • Metacarpal IV – ring finger
  • Metacarpal V – little finger
5
Q

Describe the proximal and distal articulations of the metacarpal bones

A
  • Proximal: metacarpals articulate with the carpal bones
  • Distal: metacarpals articulate with the proximal phalanges
6
Q

Describe the structure of the metacarpal bones in the hand

A
  • Each metacarpal consists of a base, shaft and a head
  • The medial and lateral surfaces of the metacarpals are concave, allowing attachment of the interossei muscles
7
Q

The phalanges are the bones of the fingers.

Describe their structure

A
  • Four fingers have proximal, middle and distal phalanges
  • Thumb has proximal and distal phalanges
8
Q

Describe the distribution of the radial and ulnar arteries in the hand

A

- Radial artery contributes mainly to supply of the thumb and the lateral side of the index finger

- Ulnar artery contributes mainly to the supply of the rest of the digits, and the medial side of the index finger

9
Q

Describe the anatomical course of the ulnar artery in the hand

A
  • The ulnar artery moves into the hand anteriorly to the flexor retinaculum, and laterally to the ulnar nerve
  • It forms the superficial palmar arch and the deep palmar branch
  • The superficial palmar arch gives rise to palmar digital arteries and then anastamoses with a branch of the radial artery
10
Q

Where is the superficial palmar arch found?

A

The superficial palmar arch is found superficial to the flexor tendons in the hand and deep to the palmar aponeurosis

11
Q

Describe the anatomical course of the radial artery in the hand

A
  • The radial artery enters the hand dorsally through the floor of the anatomical snuffbox and turns medially to move between the heads of the adductor pollicis
  • The radial artery then anastamoses with the deep palmar branch of the ulnar artery, forming the deep palmar arch, which gives rise to five common digital arteries
12
Q

What is the Allen’s test?

A
  • The Allen test is a worldwide test used to determine whether the patency of the radial or ulnar artery is normal
  • It is performed prior to radial cannulation or catheterisation, because placement of such a catheter often results in thrombosis
  • Thus, the test is used to reduce the risk of ischaemia to the hand
13
Q

How does one interpret the result of the Allen’s test?

A

A positive Allen’s test means that the patient does not have dual blood supply to the hand, which is a negative indication for catheterisation or removal of the radial arteries

14
Q

What are the two types of muscles of the hand?

A
  • The extrinsic muscles
  • The intrinsic muscles
15
Q

Where are the two diffferent types of muscles of the hand located?

A
  • The extrinsic muscles are located in the anterior and posterior compartments of the forearm
  • The intrinsic muscles of the hand are located within the hand itself
16
Q

What do the two diffferent types of muscles of the hand do?

A
  • Extrinsic muscles – they control crude movements and produce a forceful grip
  • Intrinsic muscles – they are responsible for the fine motor functions of the hand
17
Q

What are the thenar muscles?

A

The thenar muscles are three short muscles located at the base of the thumb

18
Q

Identify the 3 thenar muscles

A
19
Q

State the structure, function and innervation of the thenar muscles

A
  • Structure: muscle bellies produce a bulge (thenar eminence)
  • Function: fine movements of the thumb
  • Innervation: median nerve
20
Q

Describe the structure and function of the opponens pollicis muscle

A
  • Structure: largest and deepest of the thenar muscles

- Function: opposes the thumb

21
Q

State the origin and attachment of opponens pollicis

A
  • Origin: tubercle of the trapezium and associated flexor retinaculum
  • Attachment: lateral margin of the metacarpal I
22
Q

Describe the structure and function of the abductor pollicis brevis muscle

A
  • Structure: anterior to the opponens pollicis and proximal to the flexor pollicis brevis

- Function: thumb abduction

23
Q

State the origin and attachment of the abductor pollicus brevis

A
  • Origin: tubercles of the scaphoid and trapezium and associated flexor retinaculum
  • Attachment: lateral side of proximal phalanx of the thumb
24
Q

Describe the structure and function of the flexor pollicis brevis muscle

A
  • Structure: most distal of the thenar muscles

- Function: flexes the MCPJ of thumb

25
Q

State the origin and attachment of the flexor pollicis brevis

A
  • Origin: tubercle of the trapezium and associated flexor retinaculum
  • Attachment: base of the proximal phalanx of the thumb
26
Q

What are the hypothenar muscles?

A

The hypothenar muscles are three short muscles located at the base of the little finger

27
Q

Identify the 3 hypothenar muscles

A
28
Q

Describe the structure, function and innervation of the opponens digiti minimi muscle

A
  • Structure: lies deep to the other hypothenar muscles

- Function: opposes little finger

- Innervation: ulnar nerve

29
Q

State the origin and attachment of the opponens digiti minimi muscle

A
  • Origin: hook of hamate and associated flexor retinaculum
  • Attachment: medial margin of metacarpal V
30
Q

Describe the structure, function and innervation of the abductor digiti minimi muscle

A
  • Structure: most superficial of all hypothenar muscles

- Function: abducts the little finger

- Innervation: ulnar nerve

31
Q

State the origin and attachment of the abductor digiti minimi muscle

A
  • Origin: pisiform and the tendon of the flexor carpi ulnaris
  • Attachment: base of the proximal phalanx of the little finger
32
Q

Describe the structure, function and innervation of the flexor digiti minimi brevis muscle

A
  • Structure: lies laterally to the abductor digiti minimi

- Function: flexes the MCPJ of little finger

- Innervation: ulnar nerve

33
Q

State the origin and attachment of the flexor digiti minimi muscle

A
  • Origin: hook of hamate and adjacent flexor retinaculum
  • Attachment: base of the proximal phalanx of the little finger
34
Q

What are the lumbricals?

A

The lumbricals are 4 intrinsic muscles of the hand that flex the MCPJs and extend the IPJs

35
Q

Describe the function and innervation of the lumbricals

A
  • Function: MCPJ flexion, IPJ extension at each finger
  • Innervation:

I. Medial two lumbricals – ulnar nerve

II. Lateral two lumbricals – median nerve

36
Q

State the origin and attachment of the lumbricals

A
  • Origin: tendon of the flexor digitorum profundus
  • Attachment: pass dorsally and laterally to inserts into the extensor hood
37
Q

What are the interossei muscles?

A
  • The interossei muscles are 7 intrinsic muscles of the hand located between the metacarpals
  • They can be divided into two groups: the dorsal and palmar interossei
38
Q

Describe the structure, function and innervation of the dorsal interossei muscles

A
  • Structure: most superficial of all dorsal muscles (4 muscles)

- Function: finger abduction at the MCPJ

- Innervation: ulnar nerve

39
Q

State the origin and attachment of the dorsal interossei muscles

A
  • Origin: lateral and medial surfaces of the metacarpals
  • Attachment: extensor hood and proximal phalanx of each finger
40
Q

Describe the structure, function and innervation of the palmar interossei muscles

A
  • Structure: located anteriorly on the hand (3 muscles)

- Function: finger adduction MCPJ

- Innervation: ulnar nerve

41
Q

State the origin and attachment of the palmar interossei muscles

A
  • Origin: medial or lateral surface of a metacarpal
  • Attachment: extensor hood and proximal phalanx of same finger
42
Q

Describe the structure, function and innervation of the palmaris brevis muscle

A
  • Structure: small, thin muscle, found superficially in the subcutaneous tissue of the hypothenar eminence

- Function: wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand (improving grip)

- Innervation: ulnar nerve

43
Q

State the origin and attachment of the palmaris brevis muscle

A
  • Origin: palmar aponeurosis and flexor retinaculum
  • Attachment: dermis of the skin on the medial margin of the hand
44
Q

Describe the structure, function and innervation of the adductor pollicis muscle

A
  • Structure: large triangular muscle with two heads (radial artery passes between to form deep palmar arch)

- Function: thumb adduction

- Innervation: ulnar nerve

45
Q

State the origin and attachment of the adductor pollicis muscle

A
  • Origin:

I. One head – metacarpal III

II. Other head – capitate and adjacent areas of metacarpals II and III

  • Attachment: base of the proximal phalanx of the thumb
46
Q

Describe the cutaneous distribution of the ulnar nerve in the dorsum and palm of the hand

A
47
Q

Describe the cutaneous distribution of the median nerve in the palm and dorsum of the hand

A
48
Q

Describe the cutaneous distribution of the radial nerve in the palm and dorsum of the hand

A
49
Q

Which joints are most affected in osteoarthritis of the hand?

A
  • Distal interphalangeal joints (most often affected)
  • Proximal interphalangeal joints
  • Carpometacarpal joints (at base of thumb)
50
Q

What is carpometacarpal osteoarthritis?

A
  • Carpometacarpal osteoarthritis is a reparitive joint disease affecting the first carpometacarpal joint
  • This joint is formed by the trapezium bone of the wrist and the first metacarpal bone of the thumb and because of its relative instability, is a frequent site for osteoarthritis
51
Q

What is a boxer’s fracture?

A
  • A boxer’s fracture is a fracture of one of the metacarpal bones of the hand
  • The fracture occurs transversely across the neck of the bone, after the patient strikes an object with a closed fist
52
Q

What is Dupuytrens contracture?

A
  • Dupuytren’s contracture is a clinical condition where 1/more fingers become permanently bent in a flexed position due to the thickening of the connective tissue in the palm
  • It begins as small hard nodules under the skin of the palm then worsens over time until the fingers can no longer be straightened
53
Q

What is reflex sympathetic dystrophy?

A
  • Reflex sympathetic dystrophy (CRPS 1) is a clinical syndrome of the SNS with unknown cause characterised by pain, swelling, and vasomotor dysfunction of an extremity
  • It is associated with injury to the nerves, trauma, surgery, CVD and infection
54
Q

What is arthritis?

A
  • Arthritis is a clinical condition characterised by inflammation and stiffness of a joint
  • It presents with pain, swelling and stiffness, erythema and an abnormal gait
55
Q

What is osteoarthritis?

A
  • Osteoarthritis is the most common form of arthritis and causes the joints to become painful and stiff due to ‘wear and tear’
  • The articular surfaces wear away, presenting with a narrow joint space and severely painful bone grinding reducing one’s range of movement
56
Q

What are the 4 X-ray features of osteoarthritis?

A
  • Joint space narrowing
  • Subchondral sclerosis (thin layer of increased bone density)
  • Osteophytes (bony spurs)
  • Subchondral cysts (fluid filled sacs)
57
Q

What is a scaphoid fracture?

A
  • A scaphoid fracture is a fracture of one of the carpal bones, presenting as tenderness over the anatomical snuffbox and often has delayed presentation in X-rays (notable swelling)
  • It needs to be reduced quickly and untreated, can lead to avascular necrosis
58
Q

What is ulnar claw?

A
  • Ulnar claw is a clinical condition resulting from the long term damage of the ulnar nerve which presents as hyperextension of MCPJs (little and ring fingers) and flexion of the IPJs
  • The interossei muscles and the medial lumbricals are paralysed but the two muscles in the forearm are unaffected (laceration occurs at the wrist)
59
Q

What is the hand of benediction?

A
  • The hand of benediction is a clinical condition which occurs as a result of prolonged compression or injury of the median nerve at the forearm or elbow
  • The thenar eminence is wasted, due to atrophy of the thenar muscles and if the patient tries to make a fist, only the little and ring fingers can flex completely