Subtalar Joint Flashcards
the subtalar joint is aka
talocalcaneal joint
what type of joint is the subtalar joint
uniaxial
triplanar
what type of motion does the subtalar joint provide
supination and pronation
the subtalar joint consists of how many articulations
3
what does the posterior subtalar joint include
a concave talar facet
a convex calcaneal facet
what motion does the posterior subtalar joint provide
gliding motion
the anterior subtalar joint includes
- the middle and anterior convex talar
- concave calcaneal facets
- talonavicular articulations
what type of motion does the anterior subtalar joint provide
gliding and some rotation
what direction does the sinus tarsi run
runs FROM slightly anterior to fibular malleolus laterally TO just below the tibial malleolus medially (just superior to the sustentaculum tali )
ligaments running the entire length of the sinus tarsi help make the subtalar joint
very stable and very unlikely to dislocate
spiral of archimedes is a combination of what
a screw and a cone
often used to describe the subtalar joint
the right subtalar joint acts like a —handed screw and the left does —
right
the opposite
when the talus moves on the posterior calcaneal facet, the talus should
slide in the same direction as the gliding motion
the talus will slide in the — direction on the middle and anterior facets
opposite
as pronation motion occurs the talus advances — on the calcaneus
anteriorly
the subtalar joint axis is located:
- – from the transverse plane
- – from the frontal plane
- – from the sagittal plane
42
48
16-23
subtalar joint axis is located
-FROM lateral, posterior, plantar TO medial, anterior and dorsal.
passing though the dorsomedial aspect of the talus
the transverse plane motion will occur to a — ratio with the amount of frontal plane motion
1:1
called a mitered hinge
OKC pronation
the talus and leg may remain stationary
pronation of the subtalar joint moves the calcaneus and the foot in an abducted and everted direction (the foot moves w/ the subtalar joint)
OKC supination
the talus and leg may remain stationary
supination of the subtalar joint moves the calcaneus and the foot in an adducted and inverted direction (the foot moves with the subtalar joint)
CKC - the plantar aspect of the foot is fixed to the ground resulting in motion
superior to the subtalar joint
CKC - the movement of the calcaneus provides – plane motion
frontal
CKC - movement of the talus will provide the – plane motion
transverse
slight sagittal
CKC pronation
eversion of the calcaneus
plantarflexion and adduction of the talus
in order for the talus to provide motion in the transverse plane, the leg must
internally rotate (CKC)
CKC supination
calcaneus inverts
talus abducts and dorsiflexes
leg externally rotates
NOTE
in CKC motion virtually all of the “chain” proximal to the part will also be affected (until the other fixed end of the chain is reached)
during gait the subtalar joint provides the required — plane motion
transverse
the ankle provides no transverse plane motion
the subtalar joint and ankle joint work together to dampen the amount of
transverse plane motion required by the leg
as we move further up the kinetic chain, the screw home mechanism and transverse plane knee function further dampen
the transverse plane motion required by the thigh/hip
subtalar joint neutral position
Point in range of motion where the joint is most congruous
Point in range of motion where compression forces are maximized and torsional forces are minimized
Closed-packed position
subtlar joint neutral position (specific definition)
A point where the subtalar joint is neither pronated or supinated.
In the theoretically normal foot, the subtalar joint neutral position is 0.
subtalar varus
is a deformity in which the calcaneus is inverted with respect to the leg when the subtalar joint is in neutral position
if the subtalar joint has a varus deformity, the calcaneus will be x # of degrees – to the leg when the subtalar joint is in neutral position
inverted
NOT a “supinated” subtalar joint, but an inverted subtalar joint
subtalar valgus
is a deformity in which the calcaneus is everted with respect to the leg when the subtalar joint is in neutral position
if the subtalar joint has a valgus defortiy, the calcaneus will be x # of degrees — to the leg
everted
very rare
NOT a “pronated” foot
minimum ROM of the subtalar joint required for normal gait
4-6 ° supination
4-6 ° pronation
Total of 8-12 ° motion for normal gait
the ROM of the subtalar joint is observed in what plane
frontal plane
how can you measure the ROM of the subtalar joint
compare the posterior calcaneal bisection to a bisection of the posterior surface of the lower 1/3 of the leg
The ratio of inversion:eversion (supination:pronation) motion of the subtalar joint is
2:1
what would happen if the subtalar joint axial inclination is less than 42° (less than 42° from the transverse plane)
would be more frontal plane motion and less transverse plane motion
frontal plane dominant subtalar joint axis results in
more calcaneal motion and less talar and leg motion
low-arched, increased foot pathology
“low axis subtalar joint”
if the axial inclination angle is increased (axis has greater than normal deviation from the transverse plane)
the foot will demonstrate greater transverse plane motion
transverse plane dominant subtalar joint axis
More talar and tibial motion
Less inversion and eversion of the calcaneus
Higher arched, fewer foot problems, more postural problems (“High axis” subtalar joint or transverse plane dominant subtalar joint)
how can you measure the ROM of the subtalar joint
compare the posterior calcaneal bisection to a bisection of the posterior surface of the lower 1/3 of the leg
what would happen if the subtalar joint axial inclination is less than 42° (less than 42° from the transverse plane)
would be more frontal plane motion and less transverse plane motion
frontal plane dominant subtalar joint axis results in
more calcaneal motion and less talar and leg motion
low-arched, increased foot pathology
“low axis subtalar joint”
if the axial inclination angle is increased (axis has greater than normal deviation from the transverse plane)
the foot will demonstrate greater transverse plane motion
if the talus is moving, the — is moving
ankle
when the talus moves in CKC motion with the heel on the ground, what joints are moving
ankle joint
subtalar joint
the motion at the ankle joint occurs — to the motion of the subtalar joint
opposite
the ankle and subtalar joint togeter are referred to as
the rearfoot complex bc functionally dependent on each other
in CKC subtalar joint motion, frontal plane motion occurs with
inversion and eversion of the calcaneus
in CKC the subtalar joint motion, sagittal and transverse plane motion are provided by
the talus
in CKC pronation of the subtalar joint the calcaneus — and the talus — and —
everts
plantarflexes + adducts
in CKC pronation of the subtalar joint, pronation is occuring at what joint
subtalar joint
in CKC pronation of the subtalar joint, supination is occurring the what joint
ankle joint as plantarflexion and adduction of the talus occurs relative to the ankle joint
in CKC supination of the subtalar joint the calcaneus —, the talus — and —
inverts
abducts + dorsiflexed
in CKC supination of the subtalar joint, the subtalar joint is
supinating
in CKC supination of the subtalar joint, the talus is
dorsiflexing and abducting relative to the ankle, therefore the ankle joint is pronating
