subtalar joint Flashcards

1
Q

articulation

A

formed by 3 separate plane articulations

b/w the talus superiorly and the calcaneus inferiorly

together they will provide triplaner movement around a single joint axis

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2
Q

what is normal ROM and fxining of this joint critical for

A

dampening the rotational forces imposed by the body weight while maintaining contact of the foot with the supporting surface

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3
Q

what does the talocalcaneal joint prevent

A

unwanted movements

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4
Q

3 articular facets

A

posterior

anterior and medial

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5
Q

posterior facet

A

concave on convex

largest of the 3 facets

concave talus articulating w/ a convex facet on the body of the calcaneus

has its own joint capsule

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6
Q

anterior and medial facet

A

convex facets on the inferior body and neck of the talus and 2 concave facets on the calcaneus

2 articulations will share a joint capsule w/ the talonavicular joint

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7
Q

subtalar joint ligaments

A

very stable joint with strong ligamentous support

4 major ligaments

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8
Q

4 major ligs of the subtalar joint

A

interosseous talocalcaneal lig

ligamentum cervicis

posterior talocalcaneal ligaments

lateral talocalcaneal ligaments

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9
Q

arthrokinematics

A

complex twisting or screw like motion

can continue only until the posterior and anterior and middle facets can no longer accommodate the simultaneous and opposite motions

posterior facet –> glide is in the same direction

anterior and middle facets –> glide is in the opposite directions

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10
Q

arthrokinematics motion

A

rotation

_d/t the different shapes of the articular facets

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11
Q

result of complex arthrokinematics

A

triplanar motion of the talus around a single oblique joint axis

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12
Q

subtalar joint is a

A

uni-axial joint w/ 1 degree of freedom

allows for supination and pronation

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13
Q

supination and pronation

A

component motions w/ movement in each of the 3 planes

component motions DO NOT OCCUR INDEPENDENTLY

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14
Q

subtalar joint can

A

ABD/ADD

invert/evert

PF/DF

but will always happen together

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15
Q

OKC movements

A

talus is fixed and the calcaneus and the more distal segments of the foot move on it

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16
Q

OKC supination

A

combination of

ADD (around a vertical axis)

inversion (around an A-P axis)

PF (around a frontal axis)

17
Q

what bone moves in OKC supination

A

calcaneus and distal segments of the foot

18
Q

calcaneus is in what position during OKC supination

A

varus

19
Q

OKC pronation

A

combo of

ABD (around a vertical axis)

eversion (around an A-P axis)

DF (around a frontal axis)

20
Q

what bone is moving during OKC pronation

A

calcaneus and the distal segments of the foot

21
Q

what position is the calcaneus in during OKC pronation

A

valgus

22
Q

pronation was once called

A

eversion

23
Q

supination was once called

A

inversion

24
Q

axis of motion OKC

A

orientation of the axis is inclined

42 degrees upward and anterior from the transverse plane

inclined medially 16 degrees from the sagittal plane

25
Q

subtalar neutral OKC

A

point in which the calcaneus will invert twice as many degrees as it will evert

26
Q

CKC arthro

A

calcaneus is fixed

but is capable of some inversion and eversion with the foot on the group

cannot DF/PF or ABD/ADD (Completed by the talus)

27
Q

CKC supination

A

calcaneus will invert

talus will ABD (ER) and DF

28
Q

CKC pronation

A

calcaneus will every

talus will ADD (IR) and PF

29
Q

talar ABD/ADD is sometimes referred to as

A

IR (ADD), medial rotation

ER (ABD), lateral rotation

d/t occurring on the vertical axis

30
Q

if the mortise moves (CKC)

A

the talus moves

most congruent joint in the body

31
Q

in WB positions…

A

the lower leg and the subtalar joint are mechanically linked

motion of the lower leg will influence the subtalar joint

motions of the subtalar joint will influence movement at the lower leg

32
Q

lateral rotary force is imposed on the leg

A

lateral motion of the tibia carries the ankle mortise and the trochlea of the talus laterally

if the talus laterally rotates (ABD), then the other component motions must occur

when the talus ABDs, it will also DF and the calcaneus will invert (occur simultaneously)

33
Q

what if the subtalar joint is forced into pronation by uneven terrain

A

talar PF and ADD

calcaneal eversion

the ankle mortise is carried with the subtalar joint and will result in medial rotation of the tibia

34
Q

what can the subtalar joint do d/t the mechanical link

A

absorb lateral and medial rotary forces/movements with pronation and supination

35
Q

does the mechanical link exist in OKC

A

no

36
Q

calcaneal movement

A

easily measured

10 degrees of eversion

20 degrees of inversion

37
Q

supination ROM

A

limited by the ligamentum cervicis

considered the closed packed position

lig tension is the greatest

draws articulating surfaces together

38
Q

pronation ROM

A

limited by interosseous talocalcaneal ligament

position of mobility for the foot