midtarsal joint Flashcards
what are the degrees of longitudinal axis of midtarsal joint? primarily what motino?
15 deg transverse plane
9 deg sagittal plane
primarily frontal plane: inversion eversion
what is the characteristics of the LA of MTJ
allows forefoot to plantargrade while rearfoot is pronating/supinating
allows forefoot to invert on everted rearfoot, and evert on inverted forefoot
oblique axis degrees on planes? predominantly what motions?
52 deg transverse plane
57 from sagittal plane
primary motions: plantarflexion with adduction/ dorsiflex with abduction
what is the characteristics of oblique axis in MTJ
“second ankle joint” motion– can compensate for lack of ankle dorsiflexion
what happens to MTJ when STJ pronates
MTJ becomes more parallel and unlocks MTJ–allows foot to become mobile adaptor
relation of STJ supination to MTJ
MTJ axes become crossed/perpendicualr and locks the MTJ –>becomes rigid ever for push off
what is the most stable vs unstable position for MTJ
most stable: MTJ pronated
most unstable: MTJ supinated
oblique axis and LA in OKC
OA: pronated, LA: supinated
what is the most stable position for MTJ and STJ
MTJ: pronation
STJ: supination
when does the windlass mechanism occur? what is its effect
on the oblique axis during propulsion when it is supinated
as heel lifts during gait, toes passively dorsifle and the metatarsal heads are the pulley mechanism,
plantar fascia tightens aiding in arch rise, heel rise and compression of bones
what controls the MTJ ROM vs position
MTJ ROM is passively controlled by position of the subtalar joint
MTJ GRF control MTJ position during stance phase, and controlled by surrounding muscles during other phases
tibialis anterior inverts longitudinal axis
peroneus tertius and EDL pronates oblique to help shift weight from lateral to medial side
how does STJ supination/pronation affect MTJ
supination: decrease MTJ ROM
pronation: increase in MTJ ROM
forefoot varus vs forefoot valgus
varus: 1st met head higher than 5th
valgus: 5th met head higher than 1st
compensation of forefoot varus
calcaneus will evert to same degree of forefoot varus
uncompensated vs partially forefoot varus
forefoot varus greater than calcaneal eversion–>calcaneus unable to evert past neutral =uncompensated
partially: same as above but calcaneus able to ever past neutral but not at same degree as varus
