wrist joints Flashcards

1
Q

primary role of the wrist

A

control the length-tension relationship

permit fine adjustment of grip

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2
Q

wrist complex is composed of how many joints

A

2 compound joints

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3
Q

when the wrist cant do its job

A

nothing can do its job

nothing can compensate for the wrist

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4
Q

radiocarpal joint

A

articulation of the radius and radioulnar disk proximally w/ the scaphoid, lunate and triquetrum distally

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5
Q

does the ulnar articulate with the carpal bones

A

NO

separated by the radioulnar disk

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6
Q

the proximal surface is _______

A

biconcave

radius and the disk

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7
Q

parts of the proximal surface

A

lateral radial facet

medial radial facet

radioulnar disk

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8
Q

lateral radial facet

A

articulated w/ the scaphoid and accounts for approximately 46% of the articular surface

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9
Q

medial radial facet

A

articulates with the lunate and accounts for approximately 43% of the articular surface

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10
Q

radioulnar disk

A

articulates w/ the triquetrum and accounts for approximately 11% of the articular surface

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11
Q

which way does the biconcave surface face

A

volarly (palmarly) and ulnarly

tilted down and out

allows for more flexion than extension and more ulnar deviation than radial deviation

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12
Q

what bony architecture also limits motion in the wrist

A

dorsal lip on the radius –> limited extension ROM

radial styloid process extends further than ulnar styloid –> radial deviation is limited

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13
Q

midcarpal joint

A

articulation b/w scaphoid, lunate and triquetrum proximally

trapezium, trapezoid, capitate and hamate distally

considered a functional rather than an anatomic unit

no single continuous articular surface

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14
Q

midcarpal joint articular surface has

A

2 parts

medial joint surface

radial joint surface

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15
Q

medial joint surface

A

articulation of lunate and triquetrum proximally w/ the capitate and hamate distally

lunate and triquetrum are concave (proximal surface)

hamate and capitate are convex (distal surface)

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16
Q

how does the medial joint surface move

A

distal moves on proximal surface

bone motion and roll in the same direction

glide opposite direction

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17
Q

lateral joint surface

A

articulation of scaphoid proximally with the trapezium and trapezoid distally

scaphoid is convex

trapezium and trapezoid are concave

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18
Q

how does the lateral joint surface move

A

bone motion, roll and glide in the same direction

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19
Q

intercarpal joints

A

articulation b/w individual carpal bones

play a small role in overall wrist movement

these joints primarily glide on each other

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20
Q

what kind of joint is the radiocarpal joint

A

bi-axial joint with 2 degrees of freedom of motion

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21
Q

movements of the radiocarpal joints

A

allows for flexion and extension in the sagittal plane around a frontal (x-axis)

allows for radial deviation in the frontal plane around a sagittal (z) axis

allows for circumduction (combination of all the movements), not a true degree of freedom

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22
Q

what is the midcarpal joint

A

a condyloid joint with two degrees of freedom

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23
Q

what motions does the midcarpal joint allow

A

allows for flexion and extension in the sagittal plane around a frontal (x-axis)

allows for radial deviation in the frontal plane around a sagittal (z) axis

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24
Q

arthrokinematics of radiocarpal joint

A

convex moving on concave

biconvex (scaphoid, lunate and triquetrum) moving on biconcave (radius and disk)

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25
Q

radiocarpal flexion arthrokinematics

A

bone motion and role –> anterior

glide –> posterior

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26
Q

radiocarpal extension arthrokinematics

A

bone motion and roll –> posterior

glide –> anterior

27
Q

radiocarpal joint radial deviation arthrokinematics

A

bone motion and roll –> radial direction

glide –> ulnar direction

28
Q

radiocarpal joint ulnar deviation arthrokinematics

A

bone motion and roll –> ulnar direction

glide –> radial direction

29
Q

midcarpal joint arthrokinematics

A

medial surface is convex (hamate and capitate) moving on concave (lunate and triquetrum)

bone motion and roll same direction

glide opposite direction

convex moving on concave

30
Q

flexion of the midcarpal arthrokinematics (medial)

A

bone motion and roll –> anterior

glide –> posterior

31
Q

extension of the midcarpal arthrokinematics (medial)

A

bone motion and roll –> posterior

glide –> anterior

32
Q

radial deviation of the midcarpal joint (medial) arthrokinematics

A

bone motion and roll –> radial direction

glide –> ulnar direction

33
Q

ulnar deviation of the midcarpal joint (medial) arthrokinematics

A

bone motion and roll –> ulnar direction

glide –> radial direction

34
Q

lateral surface of midcarpal joint surface

A

concave (trapezoid and trapezium) moving on convex (scaphoid)

glide, bone motion and roll are in the same direction

35
Q

lateral midcarpal joint flexion

A

everything goes anterior

36
Q

lateral midcarpal joint extension

A

everything goes posterior

37
Q

lateral mid carpal joint RD

A

everything goes radially

38
Q

lateral midcarpal joint UD

A

everything goes ulnarlly

39
Q

how do the midcarpal and radiocarpal joints move

A

no muscles that exert direct force at the radiocarpal joint

this joint acts as a mechanical link b/w the radius and the distal carpals (b/c these areas do have muscle force actually applied)

motions at the wrist are caused by a combination of active and passive forces

40
Q

extension of the wrist

A

events occurs from full flexion to full extension

full flexion

neutral flex/ext

neutral to 45 degrees of extension

45 degrees of extension towards full extension

41
Q

full flexion (first step in extension)

A

initiated as the distal carpal row (capitate, hamate, trapezoid and trapezium) glide on the relatively fixed proximal row

wrist extensors then contract –> midcarpal joint moves –> distal row glides onto the proximal row

42
Q

neutral flexion/extension (step 2 of extension)

A

the capitate and scaphoid link together into a close packed position via ligamentous tension

the scaphoid is now considered a part of the distal carpal row

as the wrist continues to move, the scaphoid will move with the distal carap row

43
Q

neutral to 45 degrees of extension (3rd step to extension)

A

this distal carpal row and the linked scaphoid move on the relatively fixed lunate and triquetrum

still midcarpal joint motion

44
Q

45 degrees of extension towards full extension (4th step)

A

the scaphoid and lunate and brought into a close-packed position

this unites all the carpals and causes them to function as a solid unit

all the carpal will now move together as one unit

45
Q

full extension (last step of extension)

A

wrist extension is completed as the proximal articular surface of the carpals moves as a solid unit on the radius and radioulnar disk

the entire wrist complex is in a close packed position when full extension is reached

46
Q

normal ROM for extension

A

0-70 or 80 degrees

35 degrees from radiocarpal joint

40-45 degrees from midcarpal

47
Q

axis of movement for extension

A

changes throughout the ROM

48
Q

what limits extension

A

anterior capsule

volar radiocarpal ligament

ulnar-carpal ligament

49
Q

what happens if there is a tear or trauma to the wrist

A

none of this process of extension will happen

muscle has to work harder d/t no assistance from the ligaments

ex: tennis elbow

50
Q

wrist flexion

A

sequence is reversed from extension

wrist flexors contract to move radiocarpal joint –> midcarpal joint

progress to an unlocked (open-packed position)

51
Q

normal ROM for flexion

A

0-85 degrees

52
Q

axis of movement for flexion

A

changes throughout the ROM

53
Q

what limits flexion

A

posterior capsule

dorsal radiocarpal ligament

54
Q

radial deviation sequence

A

distal carpal row moves radially on the proximal row (midcarpal joint)

as motion continues, the carpals will lock together d/t ligamentous tension and begin to move as a single unit

this single unit will slide ulanrly on the radius and radioulnar disk

scaphoid and lunate will flex, while the distal row will extend, to accommodate for narrowing space b/w trapezium and the radial styloid process

55
Q

normal ROM RD

A

0-25

56
Q

axis of movement RD

A

through the capitate in anterior to posterior direction

57
Q

what limits RD

A

ulnar collateral ligament

medial capsule

bony contact

58
Q

ulnar deviation sequence

A

distal carpal row moves ulnarly until checked by ligaments

simultaneously the hamate is pulled proximally, causing the proximal carpals to spread and slide radially until checked by the radial ligaments

the scaphoid and lunate will extend while the distal carpals will flex

59
Q

normal ROM UD

A

0-45

60
Q

axis of movement UD

A

through the capitate in anterior to posterior direction

61
Q

what limits UD

A

radial collateral ligament

lateral capsule

62
Q

what joint is most important

A

MIDCARPAL JOINT!!!!!

63
Q

what gives us motion

A

not only active forces that gives us motion, but also passive movement by the ligaments so that other muscles can do their jobs

no active muscles working on the radiocarpal joint

linked by ligamentous tension