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56 Cards in this Set
- Front
- Back
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what is static stance
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a state of bipedal support of body weight during which all bones of the foot remain nearly motionless
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what is the distribution of weight on feet in static stance
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1/4 forefoot
1/4 heel 1/2 midfoot |
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what allows the midfoot to bear the most weight
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arches
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what is relationship in parts in weight bearing of the metatarsal heads
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first met=2 parts
2-5 mets=1 part 2:1:1:1:1 |
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where does the normal loading axis of the foot run
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between the center of the trochlea of the talus and the 2nd intermetatarsal space
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if the loading axis is shifted medially where is most of the weight born
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on the first and second metatarsals
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what would cause a medial shift in the loading axis
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abducted forefoot
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if the loading axis is shifted laterally where is most of the weight born
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lateral metatarsal heads
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what would cause a lateral shift in the loading axis
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adducted forefoot
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in order for the forefoot to bear 1/4 of the body weight what must happen
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gastrocnemium must fire
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what must happen to the force of the achilles in order for the forefoot to bear weight
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force of achilles must exceed force of the load on the tibia before the forefoot will bear weight
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what makes up the base of support for the feet
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the lateral margins of both feet
posterior margins of both feet metatarsophalangeal joints of both feet |
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what are the conditions of a normal foot in static stance
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the legs and sagittal bisection of the calcaneus are perpendicular to the ground and parallel to each other
subtalar joints in both feet are in neutral Heel bisection perpendicular to the ground midtarsal joints are locked in their fully pronated positions (forefoot is perpendicular to heel bisection) |
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when is the midtarsal joint fully locked
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pronated
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When is the STJ fully locked
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supination
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how are forces acting on the foot in gait increased
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weight of the person
acceleration of the person |
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what are all the forces acting on the foot during gait
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ground reactive forces
forces of mass acceleration muscle tension at joints |
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during stance phase how does a foot achieve stability
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through bone compression, muscle contraction, and little or no ligament tension
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what is the phasic activity of muscles in gait
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muscles undergoing contraction at certain time periods of the gait cycle to exert their force
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what is the function of the phasic activity of muscles during gait
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resist rotary movements at joints and ground reactive forces
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why do rotational movements increase in a pronated foot
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because the angles between bones increase and the angle that forces interact across a joint also increase
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what provides emergency stability when sudden unanticipated motion of one or more joints occur
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ligaments
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how do ligaments help stabilize joint in emergency situation
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tension on ligament lengthen resistance to emergency rotational force
stretch stimulates proprioceptors which through reflex cause muscle contraction of muscles that stabilize the joint |
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what are the possible outcomes of ligamentous failure
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ligament sprain
ligament rupture avulsion fracture(pull bone away from self where lig attached) joint damage due to compression of articular surface total dislocation |
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what is the result of abnormal shifting of weight bearing bones
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excessive shearing forces between bones and surrounding soft tissue which are fixed against shoe gear
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what are the external signs of abnormal shifting of a hypermobile foot
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corns calluses neuromas
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what other things might subluxation cause
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ligament strain, muscle fatigue, joint defomities, hallux abductor valgus, hammer toes, hallux limitus
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what does subluxation in young feet lead to
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abnormal bone structure
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what does subluxation in adult feet lead to
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degenerative joint disease such as traumatic arthritis
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what is compensation
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change in structure, position, function of one part in an attempt by the body to adjust to a deviation of structure, position, or function of another part
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what are the two types of compensation
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normal
abnormal |
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what is normal compensation
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motion in which the foot moves to adjust for irregularities of the supporting terrain or deviations in the position of any part of the trunk or lower extermities
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what is normal compensation necessary for
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to maintain postural equilibrium
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what is abnormal compensation
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motion in which the foot moves to adjust for abnormal structure or function of the trunk or lower extermity
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where does compensation normally occur at
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STJ and Midtarsal Joints
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pronation of the STJ does what to the rearfoot
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everts the rearfoot
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supination of the STJ does what to the rearfoot
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inverts the rearfoot
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when does the midtarsal joint lock on the rearfoot
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when both the longitudinal and oblique axis are maximally pronated
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what is the compensation for STJ pronation (rearfoot eversion)
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supination of the longitudinal midtarsal joint axis (inversion of forefoot)
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what is the relationship between forefoot inversion and rearfoot eversion
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there must be the same degree of eversion and inversion
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what is normal midtarsal compensation for rearfoot
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1st ray dorsiflexes MTJ unlocks foot bears weight primarily on 2nd met head
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what can the forefoot not compensate for
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rearfoot supination
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what is normal compensation for forefoot inversion by terrain
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if angle of tilt does not exceed amount of inversion avialable at the forefoot the forefoot only compensates
in angle of tilt exceeds that amount of inversion available at the forefoot then the rearfoot inverts the extra degrees required for compensation |
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what is normal compensation for eversion due to terrain
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forefoot and rearfoot evert together to compensate because MTJ is locked on the rearfoot due to lateral pressure
forefoot ends up everting slightly more than the rearfoot |
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what is normal compensation for STJ supination by terrain
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sudden demand for STJ supination can result in instability leading to equilibrium loss and possible lateral instability
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what are the results of abnormal compensation
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abnormal locomotor function of the foot
abnormal position of the foot or part of the foot |
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what is forefoot varus
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structural inversion of the forefoot on the rearfoot when the MTJ is locked
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what is the abnormal compensation for forefoot varus
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STJ pronation through midstance and propulsion
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what is rearfoot varus
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rearfoot STJ neutral position is inverted
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what is the abnormal compensation for rearfoot varus
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STJ pronation during midstance to equalize ground reactive forces across the plantar heel
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what is forefoot supinatus
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soft tissue contracture causing forefoot to be inverted on the rearfoot
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what is the compensation for forefoot supinatus
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supination of the LMTJA creating osseous instability of the forefoot
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what is the usual cause of forefoot supinatus
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by influence of tight gastro/soleus complex and its effect on the foot
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what is rigid plantar flexed first ray
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the first metatarsal in structurally plantarflexed
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what is compensation for rigid plantar flexed first ray
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supination of the STJ in contact period
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what are some of the results of rigid plantar flexed first ray
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result in muscle imbalance and possible lateral instability
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