1st and 5th Rays Flashcards
which 3 main muscles insert into the 1st ray
- peroneus longus
- tibialis anterior
- tibialis posterior
other than the 3 main muscles, which other muscles affect the 1st ray (6)
- FHL
- FHB
- EHL
- EDB
- ABH
- ADH
what is the 1st ray axis of motion
- 45° to sagittal plane
- 45° to frontal plane
therefore, equal dorsiflexion with inversion
and plantarflexion with eversion
what must the 1st ray do in gait, in order for the 1st MTPJ to dorsiflex sufficiently
it must plantarflex - move down and out of the way to allow a minimum of 65° of dorsiflexion for ‘normal’ gait
what can happen if the bones ‘jam’ in gait - i.e., hallux limitus
damage to the joint surfaces, resulting in loss of motion over time
in Closed Kinetic Chain: how do the ground reaction forces alter the function of the 1st ray
relative plantarflexion is a result of:
* subtalar supination
* midtarsal pronation
* muscles actively pulling the tarsal bones up and back
how do the sesamoids function in propulsion
they remain in contact with the ground, and the metatarsalhead rotates around them
what is high gear and low gear propulsion
- high gear: through 1st and 2nd met heads - efficient
- low gear: through 2-5th met heads - inefficient
what is a hypermobile 1st ray
if the subtalar joint pronates when it should supinate, the windlass mechanism won’t work, thus making the 1st ray mobile when it should be acting as a rigid lever
what problems can occur as a result of a hypermobile 1st ray
- hallux limitus
- hallux abducto valgus
what can cause an acquired dorsiflexed 1st ray (2)
- tibialis anterior contraction
- concurrent with forefoot supinatus
what can cause an acquired plantar flexed 1st ray (3)
- peroneus longus spasm
- weak tibialis anterior
- secondary to other deformity
what is forefoot valgus
forefoot is everted in relation to rear foot
what is forefoot varus
forefoot is inverted in relation to rear foot
in what plane of motion do rays 2, 3 and 4 move mainly
sagittal plane - plantar flexion and dorsiflexion
