Ankle and Foot Joints Flashcards
tibiofibular joints
- superior tibiofibular
- interosseous membrane
- inferior tibiofibular joint/syndesmosis
ligament functions
of tibiofibular joints
- keep fibula attached and aligned with tibia
- resist downward pull of muscles that attach to fibula
- allow fibula to move upward during dorsiflexion
superior tibiofibular joint
synovial plane for gliding during dorsiflexion but cannot move independent of inferior
-has open synovial cavity
flat facets on fibular head + postlat tibial condyle
interosseous membrane
connects shafts of tib and fib
inferior tibiofibular joint
aka tibiofibular syndesmosis
moves very slightly during dorsiflex to accomodate trochlea of talus so essential for stability
-holds lateral malleolus tight to talus
ankle joint
function
bears weight @ point where transfer from leg to foot
dorsiflex and plantarflex
bones of ankle joint
malleolar mortise = deep socket for trochlea, 3 bones + ligs
tibia-talus articulates @ inferior surface tibia w/trochlea and medial malleolus tibia w/medial talus
fibula-talus articulates @ lateral malleolus and lat trochlea
trochlea aka talus
ankle joint
mechanics
synovial hinge joint
greater ROM plantarflexing than dorsiflexing bc wedge shape talus so also have small movements bc looser
ab/adduction/inversion/eversion
stabilizing ligaments
ankle
- posterior tibiofibular
- medial aka delta/deltoid with 4 parts
- lateral with 3 parts
posterior tibiofibular ligament
part of inferior tibiofibular joint
posterior wall of malleolar mortis
prevents post disolcation of talus relative to tibia + stabilize during dorsi/plantarflexion
medial/deltoid ligament
ankle
parts:
1. anterior tibiotalar
2. tibiocalcaneal
3. tibionavicular
4. posterior tibiotalar
stable during eversion + prevent medial ankle subluxation
stronger than lateral lig
lateral ligament
ankle
parts:
1. anterior talofibular
2. calcanealfibular
3. posterior talofibular
stable during inversion + prevent lateral ankle subluxation
ankle sprains
almost always inversion of weight bearing/plantarflexed foot
usually lateral lig esp partial or complete tear of anterior talofibular (ATFL)
severe sprains = fracture or shear off lateral malleolus
sprain = torn ligament fibers
sprain tests
- anterior drawer: ATFL, better when more acute, test anterior subluxation
- talar tilt: ATFL + calcaneofibular lig, look for xs mobility
pott fracture
eversion injury
1. studden strong eversion pulls on medial ligs
2. shear tip of medial malleolus so not connected to tibia anymore
3. talus shifts laterally and stresses lateral lig
4. distal fibula fractures and/or lateral mallelous sheared from fibula (post tibfib lig)
5. sometimes can fracture posterior mallelous of tibia (where post tibfib attaches) = trimalleolar fracture
worry about compartment syndrome or cut off blood supply
tarsal tunnel syndrome
impinge tibial N from flexor retinaculum
-edema bc no room in tunnel
-affects medial and lateral plantar N too so intrinsic muscles and skin of sole out
-can affect medial calcaneal N but dep where split is, skin of heel out
invert/evert foot joints
- subtalar
- transverse tarsal
blood supply ankle joint
basics
anastomosis around ankle and all 3 major A contribute
-ant/post tibial A + fibular A
innervation of ankle joint
branches of deep fibular N and tibial N
little movement foot joitns
- tarsometatarsal - TMT
- intermetatarsal
flex/extend toes joints
- metatarsophalangeal- MTP
- interphalangeal- DIP and PIP
subtalar joint
aka talocalcaneal
synovial plane joint for weak gliding of talus on calcaneal
-slide during inversion/eversion
reinforced by 4 talocalcaneal ligs (medial/lat/post/interosseous) since weak
interosseous is most important
transverse tarsal joint
main joint for inversion/eversion and circumduction of foot
compound joint aka has lateral plane joint + medial ball and socket
-lateral = calcaneocuboid
-medial = talonavicular
reinforced by calcaneocuboid (plantar ligs + fibularis longus tendon) and talonavicular lig (spring)
tarsometatarsal joint
5 TMT joints combined = lisfranc joint
@ cuneiforms + cuboid > MT
little movement, gliding vs ant tarsals as weight redistributes
each joint has own capsule, reinforced by TMT ligs
lisfranc injury if dislocation at 1+ TMT joints
metatarsophalangeal joints
5 MTP joints @ MT > proximal phalanges
-each has own capsule reinforced by collateral @sides and plantar ligs @inferior
synovial condyloid so does all actions
bunion
hallux valgus - MT 1 misaligns, TMT and MTP joints change angle
extra lump of bone is head of MT1 not growth
interphalangeal joints
PIP and DIPs
hinge joints so only flex/extend
rein by plantar @inferior and collateral @sides ligs
arches of foot
function
inc capacity for weight bearing, shock absorption, propulsion when walking erect posture
spread forces to reduce wear/tear
3 arches of foot
- medial longitudinal, main arch, high
- lateral longitudinal arch, flatter
- transverse arch
spring ligament
aka plantar calcaneonavicular
supports talonavicular joint by 2 tight fitting slings crossing
medial longitudinal arch
medial longitudinal arch
contents
phalanges and MTs of I-III
+ most midfoot tarsals
+ talus
+ calcaneus
keystone head of talus,
lateral longitudinal arch
calcaneus + MTs + phalanges IV-V
keystone cuboid
supported by long and short plantar ligs and aponeurosis
transverse arch
cuneiform bones + cuboid
supported by tendons of tibialis post and fibularis longus
keystone intermediate cuneiform
