general q.61-122 Flashcards
Why doesn’t tibialis anterior and extensor hallucis longus help with dynamic stability of the medial arch?
they work anterior the the axis of sagital plane motion creating DF which flattens the medial longitudinal arch
What role do the calcaneonvicular ligaments play in stability of the medial longitudinal arch?
- the are the primarly stabilizers
2. without the spring ligament the arch will collapse
What makes up the lateral longitudinal arch?
- calcaneus
- cuboid
- lateral tow metatarsal bones
what is the function of the lateral longitudinal arch?
- transmit weight and thrust
2. it does not participate in shock absorption
what bones make the transverse arch and what are its dynamic stabilizers?
- cuneiforms and cuboid
- fibularis longus- passing under the cuboid to the base of the 1st met and medial cuneiform
- fibularis brevis- attaching to the base of the 5 metatrasl
why is the subtalar joint so important to the gait cycle?
- it lies within the vertical column of the leg and functions like a universal joint transferring force to the forefoot
- it also modifies the mobility of the other joints of foot
how does the talus normally move on the calcaneouis during closed chain pronation?
- anterior glide
- plantar flexes
- adducts
How does the subtalar joint transmit force from the ankle to the foot?
1the foot si slightly ER (20 degrees) at intitial contact
- as the foot pronates in response to loading stability of the talus is decreased
- lost of stability allows the talus to IR bringing the ankle with it and flexing the knee
- IR of the subtalar joint unlocks the mid and fore foot for dampening of GRF
How does the subtalar joint control the mobility of the midtarsal joints?
- pronation of the subtalar joint brings the axis of the talonavicular and calcaneocuboid joints parallel to each other so the hinges of the door line up and can move
- supination fo the subtalar joint causes a divergence of the midtarsal joints and locks them along with the tarsal into a relatively PF’d postion
What three actions are necessary to initiate walking?
- weight shifts towards the limb to be lifted
- weight is transfered towards the stance limb
- wieght moves forward as the body is allowed to fall forward and swing leg is lifted
What muscles are activated to initiate gait?
- in the swing leg tibialis anterior contracts to pull the tibia forward
- once the tibia passes over the axis of the tolocural joint the soleus works eccentrically to control forward motion
- ankle ankle DF and hip flexors also kick in
What are the foot rockers?
- different axis of motion through the stance phase
- heel-during loading the weight is on the heel until foot flat
- ankle- once the foot is flat motion shifts to the ankle
- metatarsal heads- as the heel lifts the axis shifts to the metatarsal heads
how does the body minimize energy loss during gait?
- it takes steps to limit shifts in center of gravity side to side or up and down
- the pelvis and legs perform theses adjustments
How do the lower extremities control shifts in center of gravity during gait and why is this important?
- heel rise at terminal stance equalizes leg lengths
- full knee extension at IC for the same reason
- it helps conserve energy
How does the pelvis play a role energy conservation during gait?
- contralateral hip drop
- horizontal rotation
- lateral displacement
What is the role of the subtalar joint during gait?
- the action of the subtalar joint dictates the function of the foot (adaptation, shock absorption, propulsion)
- pronation of the subtalar joint IR the tibia causing flexion of the knee
What is the role of the knee during gait?
- flexes during LR to dampen GRF
- extends mid to terminal stance
- flexion during swing to clear foot
- extends for IC to equalize leg length for energy conservation
At heel strike what is the position of the femur, knee, patella, tibia, talus, subtalar, calcareous, tarsals, metatarsals, MTP joints?
- femur- IR
- knee- extended
- patellar- lateral-superior
- tibia-ER
- talus-supinated
- subtalar-valgus
- calcaneous-pronated
- tarsals-lateral to medial shear
- metatarsals-tansverse arch decreases
- MTP joint- no action
At mid stance what is the position of the femur, knee, patella, tibia, talus, subtalar, calcareous, tarsals, metatarsals, MTP joints?
- femur- ER
- knee- flexed
- patellar- eccentric compression
- tibia-no action
- talus-anterior angle
- subtalar-varus
- calcaneous-supinated
- tarsals-medial arch flattens
- metatarsals-spread out
- MTP joint- no action
At toe off what is the position of the femur, knee, patella, tibia, talus, subtalar, calcareous, tarsals, metatarsals, MTP joints?
- femur- IR
- knee- extended
- patellar- lateral-compression
- tibia-no action
- talus-relatively pronated
- subtalar-
- calcaneous-
- tarsals-increased in transverse arch height
- metatarsals-first met ER
- MTP joint- passive extension
What is the shape of the proximal tib fib joint surfaces and what is its relative location?
- plane joint on the fibular surface
- tibia slight convex facet on the posterior lateral surface
- oriented posterior, lateral, and inferior
What does the capsule of the proximal tib fib joint look like?
- fibrous capsule attaching to the rim of the facet on the tibia
- 10% of the population it communicates with the tibiofemoral joint
What are the ligaments of the proximal tib/fib joint
- anterior- oblique orientation from the fibular head to the tibial condyle
- posterior- oblique oreintation from the fibular head to the lateral tibial condyle
- LCL
What are the ligaments of the distal tim/fib joint?
- interosseus- a continuation of the interosseus membrane
- anterior tibiofibular
- posterior tibiofibular
What joint has the greatest impact on the movement of the tib/fib joints?
1.the ankle
How does active movement of the the tim/fib joint occur?
- its primarily a passive joint and reactive to the movement of the ankle
- biceps femoris can move the proximal tim/fib
What are the motions of the proximal and distal tib/fib joint?
- supination- fibular head moves distally and posterior
- plantar flexion- fibular head move distal and IRs
- dorsi flexion- fibular head glide proximally and ER
- distal will compress during PF and separate during DF
how will inadequate DF influence IC?
1decreased heel rocker results in a rapid drop of the foot
2.a deformity of 20 degrees with put the foot flat at IC