Ankle/Foot Biomechanics II

pronation is a combination of what movements?

pronation is a combination of what movements?

eversion, abduction, dorsiflexion

supination is a combination of what movements?

inversion, adduction, plantar flexion

what bony structure forms the transverse arch of the foot?

cueniforms

functions of the medial longitudinal arch of the foot

load bearing, shock absorbing, mechanical support

what structures provide passive support in the medial longitudinal arch

plantar fascia, spring ligament, first tarsometatarsal joint

what motion creates tension int he fibers of the plantar fascia?

toe extension, especially of the 1st toe

where does the plantar fascia originate?

bottom of the calcaneus

name for passive and active tension to stabilize the longitudinal arch

windlass effect

midfoot and forefoot must be _________ at the end of stance phase of gait for push off power

stable

chronically dropped or abnormally low medial longitudinal arch

pes planus or flatfoot

what is lost due to pes planus?

windlass effect

arch dropped in weight bearing and non-weight bearing, unable to restore windlass effect

rigid pes planus

arch dropped only in weight wearing, more common and goes away with muscle activation

flexible pes planus

what symptoms/conditions may be caused by pes planus?

plantar fasciitis, posterior tibialis tendon injury, anterior knee pain, ACL injury

pes planus can alter _________ through the foot

load transmission

why do the forefoot and midfoot supinate with pes planus?

to compensate for excessive rearfoot pronation and keep the foot on the ground

what does over pronation due to pes planus cause at the knee?

dynamic valgus

what ankle muscle group has the greatest torque generating capacity? why?

plantar flexors, largest group that propels the foot forward during gait

How does the TA muscle work during the initial weight acceptance phase of gait

eccentrically for controlled lowering

when are the fibularis longus and brevis most active during the gait cycle?

push off the ground

how does the foot remain stable in the frontal plane during gait?

co-contraction of the tibialis posterior and peroneals

posterior conpartment muscles ________ the talocrural joint and ___________ the foot

plantar flex, supinate

how do the posterior compartment muscles work during gait?

eccentrically to lower foot, then concentrically during lifting of the heel

during stance, plantar flexors ________ the dorsiflexion of the tibia

decelerate

dynamic supporter of the arch during gait

tibialis posterior