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
What happens to blood during calf pump?
- vertical and horizontal movement of venous blood
- vertical => pressure changes generated in deep lower leg veins (anterior/posterior fib/tib veins)
- vertical => calf contracts => elevates pressure => venous blood => popliteal and femoral vein
- horizontal => deep => superficial veins
- horizontal => increase pressure => deep lower leg veins (anterior/posterior fib/tib veins) => perforating veins => saphenous vein
Miss Jones is a 35 year old police officer who often spends the majority of her shifts on foot patrol. She has recently noticed some anterior knee pain when walking which seems to be work in her work boots compared to the trainers that she usually wears on days off.
Can you describe some potential maladaption of the foot and ankle that might contribute to this?
- as she’s walking her foot in the boot might not be able to evert and adapt to the ground as effectively after heel strike
- work boots are stiff => stopping foot from everting => stops mid-tarsal (calcaneocuboid + talonavicular joints) from lining up and less mobility
- results in the inferior tib-fib joint being required to do less range of motion throughout the gait cycle; on dorsi flexion the fibular will move superiorly, the inferior tib-fib joint will move laterally and the fibular will internally rotate, which would usually stimulate soleus, one of the calf pump mechanisms
- more pressure on meniscus in rotation
- patella moves medially away from patella groove, adding tension to ACL/PCLs
- as reduced range in motion required, her body is being energy efficient and not stimulating venous return from her foot via the deep, superficial and perforating veins back to her femoral and popliteal veins
- additionally a heavy boot might create pressure changes in foot => less venous drainage
- tibia may have to compensate by rotating more internally under the femur during heel strike to assit in adapting to the fortune beneath her foot
- tibia isn’t able to internally rotate => patella may need to do more rotation to assist in ankle mobility
- where knee might move medially and internally during heel strike to assist create adaptable platform before moving laterally on stance phase to create stability
- hamstrings => stabilisation of posterior knee => hypertrophy of hamstrings + popliteus assist in walking
- heel strike => plantar fascia + tendons + muscle + ligaments lengthen + load to assist supination propulsion
- prolongued standing => calf pump reduction => muscle shortening + fixed flexion deformity of knee/hip + gait disturbances
Miss Jones is a 35 year old police officer who often spends the majority of her shifts on foot patrol. She has recently noticed some anterior knee pain when walking which seems to be work in her work boots compared to the trainers that she usually wears on days off.
Describe the potential Biomechanical mechanisms that might be involved
- ankle mortise oint allows for plantar flexion + dorsi flexion
- subtalar = eversion + inversion
- combined movement => supination + pronation
- midtarsal joint => torque conversion of forces from foot to tibia
- subtalar = torque converter = changes frontal plan movement (dorsi/plantar flexion) => calcaneous into vertical movement through tib/fib
Describe the 5 functions of the foot and ankle during locomotion
- facilitates gait
- propriception
- shock absorption
- adaptation to ground => mobility + stability
- smooths out uneven surfaces
What are the 2 key functions of the subtalar joint during locomotion?
- torque conversion of the foot into the tibia + fibula
- influences midtarsal joint and mobility/stability
Briefly describe the mechanism of the calf pump
- gastrocnemius + soleus form the calf pump, moving blood from lower limb back towards heart
- uses pressure differences to pump blood from lower leg upwards
- displacement of blood happens in vertical + horizontal planes
Which 5 factors influence impairment of calf pump function
- prolonged standing
- muscle shortening
- fixed flexed deformity of knee/hip
- gait disturbances
- inactivity/immobilisation
