1) inclined 42 degree upward and anteriorly from the transverse plane
2)inclined medially 16 degree from sagittal plane
motion about this oblique axis will cross all three planes
-the subtalar component motion are coupled and cannot occur independently
subtalar joint motions:-
1)in weight bearing subtalar joint motion:_
when an individual is WT bearing the calcaneous is on the ground and generally free to move around a longitudinal axis -inversion and eversion.
-the weight bearing calcaneous can contribute to the inversion /eversion component of motion
- but the other two couples components of subtalar motion-abduction /adductionand dorsiflexion /plantarflexion can be only accomplishe by the movement of talus on the more fixed calcaneous
-in weight bearing subtalar motion the direction of the component movements contributed by the talus in th eopposite of wat the calcaneous would contribute
supination:-
1)calcaneal inverson
2) talar abduction
3) talar dorsiflexion
pronation:-
calcaneal eversion
2)talar adduction
3)talr plantar flexion
cavus foot:-
cavus foot is a condition in which the foot has a very high arch
-because of this high arch an excessive amount of weight is place on the heel of the foot when walking or standing
flat foot:-
although subtalar joint pronation is anormal foot motion a foot that appears fixed in this position often is called pronated or pes planus
- it is a deformity that occurs when the arch of the foot collapses and comes into complete or near complete contact with ground
2)non weight bearing subtalar joint motion:_
-in this the supination and pronation of subtalar motion is described by motion of calcaneous on tyhe stationary talus and lower leg
supination:_
calcaneal inversion
2)calcaneal adduction
3)calcaneal plantar flexion
pronation;-
calcaneal eversion
calcaneal abduction
calcaneal dorsiflexion
eefcts of subtalar joint motion on the leg
1) in non weight bearing:_motion of the subtalar joint and the leg are independent
2)in weight bearing:-
for supination /pronation the coupled components motion of dorsiflexion plantar flexion and abduction / adduction require the body of talus move as well
dorsiflexion of talus:_body of talus slide posteriorly within motion
plantar flexion of talus :-body of the talus move anteriorly within the motion.
ankle joint cannot absorbs the coupled component motion of talar adduction /abduction without affecting the leg
supination :-
coupled component of talar abduction carries the mortise joint laterally-produces lateral rotation of leg
pronation:-
talar adduction carries the mortise medially..-tibia and fibula goes in into medial rotation
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