7: Subtalar Joint - Frush Flashcards
subtalar joint =
articulation b/w talus and calcaneus
the interosseous ligament limits …
inversion and eversion (more)
the cervical ligament limits …
inversion
STJ axis
42 degrees from the transverse plane
16 medial deviation from sagittal plane
motion STJ joint
inverion eversion and abduction adduction
little dorsiflexion plantarflexion
transver and frontal : sagittal
3:1
open kinetic chain supination
inversion, plantarflexion, adduction
open kinetic chain pronation
eversion, dorsiflexion, abduction
what does the STJ do during 1st and last half of OKC?
1st - pronates (allows for ground clearance)
Last - starts to supinate
just before heel strike
STJ in neutral
at heel strike
STJ supinated
what will you see during CKC?
inversion and eversion of calcaneus will be only thing externally visible
CKC supination
calcaneal inversion
talar dorsiflexion and abduction
tibial external rotation
CKC pronation
calcaneal eversion
talar plantarflexion and adduction
tibial internal rotation
CKC internal leg rotation =
talar adduction
CKC external leg rotation =
talar abduction
because CKC talus and leg are proximal to axis, will act in _______ motion of calcaneus
opposite
allows foot to become mobile adaptor and allows for shock absorption
STJ heel strike and starting to pronate
during CKC midstance, the STJ starts to …
supinate (to allow for heel off, foot becomes rigid lever)
how do you find STJ neutral?
palpate talar neck and move foot back and forth until it feels equal medially and laterally
STJ total ROM
30 degrees
20 calcaneal inversion/ supination, 10 eversion/ pronation
how do you calculate STJ neutral through ROM?
- prone pt
- bisect calcaneus and lower leg
- invert calcaneus to end ROM and measure angle
- evert calcaneus to end ROM and measure anlge
- add measurements together and divide by 3 (* if this number less than measured eversion = valgus, greater than eversion = varus)
- subtract this number from measured eversion
= calculated STJ neutral
describe the kirby method
- pt in STJ neutal nonweightbearing
- push onmedial foot and lateral foot until coming to point where foot does not move
- do at least 3 pts
- assumes the normal STJ axis passes through the posterior-lateral heel and through the first intermetatarsal space of platnar foot anteriorly
if STJ is laterally located (kirby method) …
foot supinates easily
if medially located, foot pronates more easily
