wrist joints Flashcards

(63 cards)

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
radiocarpal flexion arthrokinematics
bone motion and role --> anterior glide --> posterior
26
radiocarpal extension arthrokinematics
bone motion and roll --> posterior glide --> anterior
27
radiocarpal joint radial deviation arthrokinematics
bone motion and roll --> radial direction glide --> ulnar direction
28
radiocarpal joint ulnar deviation arthrokinematics
bone motion and roll --> ulnar direction glide --> radial direction
29
midcarpal joint arthrokinematics
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
flexion of the midcarpal arthrokinematics (medial)
bone motion and roll --> anterior glide --> posterior
31
extension of the midcarpal arthrokinematics (medial)
bone motion and roll --> posterior glide --> anterior
32
radial deviation of the midcarpal joint (medial) arthrokinematics
bone motion and roll --> radial direction glide --> ulnar direction
33
ulnar deviation of the midcarpal joint (medial) arthrokinematics
bone motion and roll --> ulnar direction glide --> radial direction
34
lateral surface of midcarpal joint surface
concave (trapezoid and trapezium) moving on convex (scaphoid) glide, bone motion and roll are in the same direction
35
lateral midcarpal joint flexion
everything goes anterior
36
lateral midcarpal joint extension
everything goes posterior
37
lateral mid carpal joint RD
everything goes radially
38
lateral midcarpal joint UD
everything goes ulnarlly
39
how do the midcarpal and radiocarpal joints move
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
extension of the wrist
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
full flexion (first step in extension)
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
neutral flexion/extension (step 2 of extension)
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
neutral to 45 degrees of extension (3rd step to extension)
this distal carpal row and the linked scaphoid move on the relatively fixed lunate and triquetrum still midcarpal joint motion
44
45 degrees of extension towards full extension (4th step)
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
full extension (last step of extension)
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
normal ROM for extension
0-70 or 80 degrees 35 degrees from radiocarpal joint 40-45 degrees from midcarpal
47
axis of movement for extension
changes throughout the ROM
48
what limits extension
anterior capsule volar radiocarpal ligament ulnar-carpal ligament
49
what happens if there is a tear or trauma to the wrist
none of this process of extension will happen muscle has to work harder d/t no assistance from the ligaments ex: tennis elbow
50
wrist flexion
sequence is reversed from extension wrist flexors contract to move radiocarpal joint --> midcarpal joint progress to an unlocked (open-packed position)
51
normal ROM for flexion
0-85 degrees
52
axis of movement for flexion
changes throughout the ROM
53
what limits flexion
posterior capsule dorsal radiocarpal ligament
54
radial deviation sequence
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
normal ROM RD
0-25
56
axis of movement RD
through the capitate in anterior to posterior direction
57
what limits RD
ulnar collateral ligament medial capsule bony contact
58
ulnar deviation sequence
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
normal ROM UD
0-45
60
axis of movement UD
through the capitate in anterior to posterior direction
61
what limits UD
radial collateral ligament lateral capsule
62
what joint is most important
MIDCARPAL JOINT!!!!!
63
what gives us motion
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