L4: Bones, ligaments and joints of the hand (incl. wrist) Flashcards

1
Q

bones of the hand

A

carpals (8)
- 2 rows of 4
metacarpals (5)
- 1st [thumb] to 5th [wee finger]
phalanges (14)
- proximal
- middle *
- distal

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2
Q

carpals

A

scaphoid
lunate
triquetrum
pisiform
trapezium
trapezoid
capitate
hamate

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3
Q

carpal tunnel

A

the carpal tunnel is formed by:
carpals: floor, medial and lateral wall
transverse carpal ligament: roof

transverse carpal ligament is aka flexor retiaculum

medial nerve enters hand from forearm by passing through the carpal tunnel

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4
Q

carpal tunnel syndrome

A

Carpal tunnel syndrome caused by compression of median nerve
Compression of median nerve usually occurs due to increased pressure in carpal tunnel

Causes:
*Injury (swelling)
*Tendon hypertrophy

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5
Q

metacarpals

A

5 in total
features: base, shaft, head
base articulates with carpals
head articulates with phalanges
thumb = 1, little finger = 5

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6
Q

boxers fracture

A

inexperienced boxers tend to hook punch

4th and 5th metacarpals are weaker than other and less well supported
they are easily fractures during hoot punches

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7
Q

phalanges

A

proximal, middle*, distal
* thumb has no middle phalanx
features:
proximal + middle phalanx: base, shaft, head
distal phalanx: base, shaft, tubercle

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8
Q

mallet finger

A

extensor tendon rupture or avulsion injury leaves distal phalanx in the flexed position

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9
Q

jersey finger

A

finger caught in jersey
due to momentum of players finger is hyperextended and the flexor tendon is torn
may also avulse a piece of bone
patient no longer able to flex finger
affected finger resides in affected position

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10
Q

wrist joint

A

complex, involves many joints:
- distal radioulnar joint
- radiocarpal joints
- intercarpal joints

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11
Q

distal radioulnar joint

A

ulnar head in ulnar notch of radius
synovial pivot joint
allows for supination and pronation of forearm

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12
Q

radiocarpal joint

A

joint between:
- distal radius/ulnar fibrocartilaginous disc
- proximal row of carpals; scaphoid, lunate, triquetrum

synovial condyloid joint
- on one side, joint capsule attached to distal radius and ulna
- on other side, joint capsule is attached to proximal carpals

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13
Q

radiocarpal joint movements

A

flexion / extension
radial deviation [abduction] / ulnar deviation[adduction]
circumduction

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14
Q

intercarpal joints

A

augment range of wrist movements

plane synovial joints
between carpals of a given row e.g. scaphoid and lunate |||

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15
Q

midcarpal joints

A

between proximal and distal row of carpals
synovial condyloid joints

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16
Q

wrist joint capsule

A

joint space is mostly continuous between wrist and hand
synovial membrane lines capsule
capsule reinforced by ligaments:
- anterior interosseous ligaments
- posterior interosseous ligaments

17
Q

wrist joint: strengthened by 6 ligaments

A

radial collateral ligament
ulnar collateral ligament
palmar ulnocarpal ligament
palmar radiocarpal ligament
dorsal ulnocarpal ligament
dorsal radiocarpal ligament

18
Q

radial collateral ligament

A

radial styloid to tubercle of scaphoid

19
Q

ulnar collateral ligament

A

ulnar styloid to triquetrum

20
Q

palmar ulnocarpal ligament

A

strengthens capsule

21
Q

palmar radiocarpal ligament

A

radius to both rows of carpal bones
fibres directed such that hand follows radius during supination of forearm

22
Q

dorsal ulnocarpal ligament

A

ulna to triquetrum

23
Q

dorsal radiocarpal ligament

A

radius to both rows of carpals
fibres directed such that hand follows radius during pronation

24
Q

colle’s fracture

A

typically due to FOOSH
fracture of radius (and sometimes ulna) approx. 2.5cm from distal end
distal radial fragment moves posteriorly and proximally
there is also dislocation of the radioulnar joint distally
dorsal surface of forearm adopts a dinner fork shape

25
smith's fracture
fall onto flexed wrist direct blow to posterior surface of distal forearm anterior and proximal displacement of distal radial fragment
26
scaphoid fracture
most vulnerable carpal to fracture usually due to fall on outstretched arm with hand in abducted position normal scaphoid anatomy: -proximal pole -wait -distal pole arterial blood supply VERY important
27
scaphoid - arterial blood supply
main arterial blood supply: dorsal scaphoid branch of the radial artery enters scaphoid at the waist, turns proximally to supply 80% of the bone the waist is the weakest part of the scaphoid. fracture here can interrupt arterial blood from reaching proximal 80% of bone distal 20-30% supplied by branches from superficial palmar arch
28
scaphoid - avascular necrosis (AVN)
waist is weakest part of scaphoid, fracture here can interrupt arterial blood supply from reaching proximal 80% of bone without arterial blood supply [avascular], proximal 80% of bone dies [becomes necrotic] ... leading to avascular necrosis [AVN]
29
where is the scaphoid
''hitch hiking'' position scaphoid at base of hollow made by thumb tendons scaphoid found in floor of ' anatomical snuffbox''
30
thumb movements
capable of wide range of movements due to its carpometacarpal joint (synovial, saddle shape) The thumb CMC joint is the joint most commonly affected by osteoarthritis The thumbs MCP joint is a synovial hinge joint Thumbs only IP joint is a synovial hinger joint
31
movement of the digits 2-5
proximal + distal IP joints: - abbreviated to PIP + DIP j - hinger synovial joints - flexion + extension MCP joints: - knuckles - condyloid synovial joints - flexion + extension - abduction + adduction - circumduction CMC joint - plan synovial joint
32
surface anatomy of wrist + hand
styloid processes of the radius and ulna
33
anatomical snuffbox - floor
scaphoid proximally trapezium distally
34
anatomical snuffbox - boundaries
extensor pollicis longus extensor pollicis brevis abductor pollicis longus