PT3 - Foot And Ankle In Locomotion Flashcards
What are the functions of the foot and ankle?
- stable platform
- mobility
- facilitates gait
- smooths out uneven ground surfaces
- proprioception
- shock absorption
Describe the global foot anatomy
- talocrural joint
- subtalar joint
- tib-fib joint
- foot arches
- calf pump mechanism
What movements and forces go through the talocrural joint?
- plantar and dorsi flexion
- limited transverse movements
- force transmitted to talus - talus directs to forefoot
- zero attachments of muscles onto the talus
Describe the movements of the subtalar joint
- torque converter
- transforms transverse movements of shank (lower leg) into frontal plan motions of rear foot and vice versa
- in the talus plantar/dorsi flexion => eversion/inversion
- influences mid-tarsal joint
- torque transfer relies on stable + mobile + shock absorbtion
- rotation in upper body => eversion/inversion of calcaneous
Which joints make up the midtarsal joint?
- talo-navicular joint
- calcaneo-cuboid joint
How many joints make up the mid tarsal joint?
- 2 joints
What happens as your foot everts?
- midtarsal joint (talo-navicular + calcano-cuboid) joints line up
- makes the foot mobile => shock absorbtion
- medial arch lowers (eversion) => malleable foot
What happens when your foot inverts?
- subtalor inversion => mid-tarsal joints (talo-navicular + calcano-cuboid) joints no longer line up
- foot becomes more ridged (arches)
What happens during supination and pronation?
- supination => stable foot structure
- pronation => mobile and sock absorbing foot structure
What happens to the foot when we heel strike?
- after heel strike the foot pronates
- plantar fascia + tendons + ligaments = lengthened + loaded with potential energy to help supination propulsion
What does the mid-tarsal joint link?
- rear foot to forefoot via talonavicular + calcaneocuboid joints
Describe the superior tib-fib joint
- flat oval synovial joint
- position maintained by ITB + Bicep femoris + lateral collateral ligaments
- common perineal nerve winds behind fibular head
Describe the inferior tib-fib joint
- bones joined by anterior and posterior ligaments + strong interosseus membrane
- dorsi flexion => interosseus membrane => taut => ankle mortise size increases => force direct across foot
Describe the mid-tib-fib joint
- fibrous union of fib + tib by interosseous membrane
- muscle attachment point
- decreased separation by weight bearing forces
What happens at the tib-fib joint in dorsi-flexion?
- inferior tib-fib moves laterally (outwards) making space for talus
- fibular moves superiorly and internally rotates
- interosseous membrane taught
What happens at the tib-fib joint in plantar-flexion?
- inferior tib fib joint moves medially
- fibular moves inferiorly and externally rotates
What is special about peroneal longus?
- controls both pronation and supernation movement
- lengthened and control in eversion and inversion
- one joint lengthening and one joint shortening
- good at creating tension
- NOT concentric and eccentric, more functional
- uses tendon + tiny muscle => synergistic tweaking tendon tension rather than contracting and relaxing the muscle
- stability exercises better than foot exercises working eversion
What happens at heel strike?
- foot everts => mobile
What happens at stance phase?
- foot transitions to inversion on grounded leg for stability
What happens at the first ray during inversion?
- first ray plantar flexes
- if no movie ment here, then ends with hallux vagus
Which muscles assist in calf pump?
- gastrocnemius and soleus
What impaires calf pump?
- inactivity/immobilisation
- muscle shortening
- fixed flexion deformity at knee + hip
- gait disturbances
- prolonged standing (gravity prevents venous return from happening => varicose veins)
Which veins are involved in venous drainage?
- superficial => great saphenous vein (superficial fascia layer)
- deep => anterior and posterior tibial veins + fibular veins (supported by muscles + fascia)
- perforating => intermediate and deep facial layers of leg (communicating between deep and superficial)
- vertical + horizontal flow of blood
What is calf pump?
- force of enhancing venous return from lower extremity to heart