1st Ray, 1st MPJ, and Lesser Rays Flashcards
What is the axis of the 1st ray?
45 deg from frontal plane
45 deg from sagittal plane
what is the direction of the 1st ray axis as it courses across the foot?
proximal-medial-dorsal
to distal-lateral-plantar
What is the total ROM of the 1st ray?
10mm
(5mm- dorsiflexion)
(5mm-plantarflexion)
what is considered a hypermobile joint?
total ROM over 15-20mm
what is the function of the 1st ray in gait?
plantarflexion of 1st ray during midstance and propulsion necessary for proper 1st MPJ function allowing dorsiflexion in toe-off
what are the requirements for `proper 1st ray function?
supinated STJ (locked) stable MTJ (supination of OA)
which muscle stabilizes the lesser tarsus and 1st met against ground allowing plantarflexion of 1st ray?
peroneus longus
what is the biggest plantar flexor muscle?
abductor hallucis
what is the function of the 1st MPJ?
dorsiflexion allows smooth, effective propulsion of the body during toe-off
how many centers of motion are within the 1st metatarsal head?
4
describe the types of motion the 1st MPJ exhibits.
- rolling motion
- sliding motion w/ 1st ray plantarflexion
- compression at end ROM
how much dorsiflexion and plantarflexion can you get for 1st MPJ?
dorsiflexion- 60 to 65 deg
plantarflexion- 5 to 10 deg
proper 1st MPJ function during gait requires what?
- stability and plantarflexion of the 1st ray
- normal sesamoid function
- normal function of 1st MPJ muscle stabilizers
what is the function of 1st MPJ in gait? (from midstance to toe-off)
hinge motion- for first 20 deg
arthroidal motion- occurs at 20 deg
what is position 1 on the 1st met head for?
rolling motion (this is hinge motion)
what is position 2 and 3 on the 1st met head for?
sliding motion (tangential motion)
what is position 4 on the 1st met head for?
compression from velocity
which positions will you use if you are walking in a leisurely gait?
positions 1,2,3
which positions are you using if you are running?
will use 1-4!
As there is an increase in _____, more positions are exposed on the 1st met head
plantarflexion
where is the axis of motion for 2nd,3rd, and 4th rays?
proximal to tarsometatarsal joint
what is the motion that occurs about the 2nd-4th rays?
pure dorsiflexion and plantarflexion
what is the axis for the 5th ray?
20 from transverse
35 from sagittal
