18/19: Orthotic Materials and Construction - Cronin Flashcards
1
Q
factors that affect selection of material thickness
A
- forces to be resisted
- body weight
- age
- activity
2
Q
factors that affect selection of materials for top covers
A
- diabetic foot protection
- need for cushion
- need for support
- durability of material
- memory of material
- thin cover for dress shoes
3
Q
posting materials
A
- cork
- crepe
- EVA
- felt (diagnostic purposes)
4
Q
how was the positive cast created?
A
pouring of the negative cast
5
Q
why is the negative cast bisected?
A
- negative cast is bisected to determine the forefoot to rearfoot relationship
- bisection technique- lateral curvature method
6
Q
how do you mark the lateral expansion?
A
- begins at the proximal lateral corner of the square represent the lateral platform and ends where the distal heelcup line and the lateral heel cup height intersect
- lateral expansion is meant to accommodate for soft tissue spread
7
Q
where will the balance platform be placed for an inverted forefoot?
A
beneath the first met head
- the balance platform will be placed beneath the fifth met head to balance for everted forefoot
8
Q
why is the lateral edge straight?
A
- horizontal grind is made along the lateral edge of the orthosis enusring thta tthe lateral heelcup height is maintained
- straight lateral edge also prevents the foot from pronating off the orthosis
9
Q
what is the purpose of the rearfoot post?
A
- stabilizes the orthosis shell
- stops excessive calcaneal eversion
- allows normal pronation-shock absorption
- normal pronation is accomplished by adding motion
- post motion is provided by grinding the medial plane
- amount of post motion is determined by sagittal plane inclination angle of the STJ axis
10
Q
what determines the height of the heelcup?
A
the height and width of the heel counter in the shoe
