Orthotic Manufacturing Flashcards
what position is the calcaneal bisection as the positive is made
perpendicular to the ground
when i the negative cast removed
when the plaster is hardened
what are the types of positive plaster modifications
- FF platform
- heel cup accommodation
- arch fill
- “sweet” spots
how is a FF platform created
- nail is placed on the plantar sufrace of the 1st (for FF varus) OR 5th (for FF valgus) MT head to prop up the positive in the appropriate position
- plaster is applied to build a platform at an angle dictated by the position of the nail
where is the calcaneal bisection when forming a FF platform
-perpendicular to the ground or FF may be “balanced” to RF
for a FF varus, where will the FF platform me thicker
medially
fore a FF valgus, where will the platform be thicker
laterally
how is a heel cup accommodation added
plaster is added around the periphery of the heel
what does a heel cup accommodation allow for
-soft tissue spread when the patient bears weight
where are arch fills added
to the medial arch to allow for soft tissue expansion and to provide a smooth transition into the FF platform
a minimal arch fill will provide for
greater control
a heavier arch fill will allow for
more flattening of the arch
how do you accommodate for “sweet spots”/bony prominence
add a small mound of plaster to the area of the prominence which will then lead to a pocket on the shell
what are the material requirements for the shell
heat moldable
able to hold their shape
where does a standard functional device extend to
- just proximal to the MT heads distally
- to the centre of the 1st MT medially
- to the centre of the 5th MT laterally