STATICS AND COMPENSATION HIGH YIELD

Question 1

name this stance:

state of bipedal support of body weight during which all bones of the foot remain nearly motionless

Answer 1

static stance

Question 2

in the static stance, what is the distribution of body weight supported by:

forefoot?
heel?
mid foot?
metatarsals?

Answer 2

1/4 of BW supported by forefoot
1/4 of BW supported by the heel
1/2 of BW supported by the midfoot
2:1:1:1:1

Question 3

what is the loading axis for normal distribution?

shifted medially
caused by?

shifted laterally
caused by?

*this is static stance

Answer 3

center of trochlea of talus
2nd inter metatarsal space

1st and 2nd metatarsals bear more of the weight
abducted foot

lateral metatarsal heads bear more of the weight
adducted foot

Question 4

what muscle must fire to 1/4 of BW on forefoot? what about the remaining?

so base of support is made of?

*this is static stance

Answer 4

gastrocnemius
feet anterior to the ankle joint

MTP joints
lateral margins of feet
posterior margins of feet

Question 5

what is the joint orientation in static stance for STJ and MTJ?

what else is affected?

why is the gastro imp?

Answer 5

neutral

locked in fully pronated positions

legs and sagittal bisection of the calcaneus are perpendicular to the ground and parallel to each other

it exerts plantarflexion moment force at ankle joint loading forefoot, but remember that no muscle support is necessary to keep structural integrity

Question 6

bones of the forefoot are moving while they bear weight, what is this called?

Answer 6

dynamic gait

Question 7

so when the faster a person walks, or heavier they are, what is the affect of the forces on the foot?

Answer 7

the greater the forces acting on the joints of the foot during gait

Question 8

what are the forces acting on the foot during gait? effects?

Answer 8

compression (linear) force
-stability
bending (tension) force
-instability

Question 9

how does normal foot function during stance phase achieve stability?

Answer 9

bone compression
muscle contraction
no ligament tension

*ligament tension helpful during structural support

Question 10

so because we know the dynamic gait is phasic activity, is muscular contraction important? the phasic activity of muscles resist?

Answer 10

yes

rotatory movements at joints and ground reactive forces

Question 11

during dynamic gait, in a pronated foot, what increases the most at joints?

Answer 11

rotational motion increases at most joints
and so muscles work harder in an unstable pronated foot to resist the rotational forces and opposite is true for supinated foot

Question 12

these serve as emergency stability when a sudden unanticipated motion of one or more joints occurs?

Answer 12

ligaments

Question 13

what is the relation between ligament and subluxation?

Answer 13

so the joint starts tension in the ligament and joint capsule of the involved joint and so as ligament lengthens, resistance to emergency rotational forces increases

Question 14

what is the effect of stretch on ligaments or the capsule?

Answer 14

it stimulates the propioceptors

Question 15

function of the ligament during emergency instability?

Answer 15

decelerates motion of subliming joint
start increased contraction of muscle to stabilize joint
keeps joint integrity intact until muscle function re-establishes the joint

Question 16

what does ligamentous failure result in?

Answer 16

ligament sprain or rupture
avulsion fracture
joint damage due to compression of articular surfaces
total joint dislocation

Question 17

what is the primary cause of mechanical trauma to foot?

Answer 17

kinetic instability during locomotion

Question 18

what is the cause/effect of kinetic instability during locomotion?

Answer 18

causes internal tissue damage which eventually manifests in external symptoms

corns, calluses, neuromas

Question 19

subluxation results in? how to fix this?

Answer 19

ligament strain
muscle fatigue
jont deformities
abnormal structure
degenerative joint disease

improvement in stability of the foot

Question 20

what are the main causes of kinetic instability during locomotion?

Answer 20

hypermobility

subluxation

Question 21

what are the two forms of compensation?

Answer 21

normal

abnormal

Question 22

these joints are the primary sites for compensation due to triplanar motion available?

which one is the primary joint in the lower extremity for compensation?

Answer 22

STJ and MTJ

STJ

Question 23

pronatory and supinators compensation are used to describe?

Answer 23

direction of compensation

Question 24

what is the effect of pronation and supination on normal compensation?

Answer 24

pronation of STJ everts rear foot

supination of STJ inverts the rear foot

Question 25

what is the effect of normal compensation on the mid tarsal joint?

Answer 25

MTJ locks on rear foot when both the long. and oblique axis are maximally pronated

Question 26

what are the factors that determine the MTJs ability to compensate for rear foot position?

Answer 26

ROM

locking position

Question 27

compensation for STJ pronation (rear foot eversion) is?

Answer 27

forefoot inversion (supination of LMTJ)

same number of degrees of forefoot inversion as rear foot eversion

Question 28

same number of degrees of forefoot inversion as rear foot eversion, if this doesn’t happen than what?

Answer 28

rearfoot pronation is only partially compensated

Question 29

what is the result when the STJ (moving the forefoot) attempts to remain in contact with the ground?

Answer 29

1st ray dorsiflexion
MTJ unlocks
foot bears weight on 2nd metatarsal head

Question 30

T/F, forefoot cannot compensate for rear foot supination?

Answer 30

true

Question 31

what does the locking mechanism of the MTJ do? what happens to the calcaneus? what about the MTJ axis?

Answer 31

prevents eversion of the forefoot

calcaneus inverts with STJ supination and so forefoot also inverts

MTJ axis is loaded maximally pronated and so locked and so no more forefoot motion can occur

Question 32

refer to MTJ and STJ compensation for terrain!!!

Answer 32

in notes

Question 33

what are the types of abnormal compensation?

Answer 33

forefoot varus
rearfoot varus
forefoot supinatus
rigid plantar flexed first ray