Orthotic and Prosthetic Design & Fabrication Flashcards

On a positive model for a patellar-tendon-bearing (PTB) socket, which area typically receives a buildup (relief)?

Answer: Fibular head

The fibular head is pressure sensitive and is relieved by adding plaster to the positive model.

Which area of the transtibial residual limb is considered pressure tolerant?

Answer: Medial tibial flare

The medial tibial flare is a broad, load-tolerant surface used for weight bearing.

Compared with a quadrilateral socket, an ischial containment transfemoral socket is characterized by:

Answer: A narrow mediolateral dimension

IC sockets narrow the ML dimension and enclose the ischium and ramus for femoral control.

In a quadrilateral socket, the anterior wall bulge over Scarpa's triangle functions to:

Answer: Hold the ischium on the posterior seat

The anterior counterpressure pushes the limb posteriorly to keep the ischial tuberosity on its seat.

When casting for a custom AFO in a patient with flexible pes planovalgus, the subtalar joint should generally be held in:

Answer: Neutral position

Subtalar neutral captures a corrected, functional foot position in the cast.

A transfemoral socket is preset in initial flexion primarily to:

Answer: Place hip extensors on stretch and accommodate any hip flexion contracture

Initial flexion improves hip extensor efficiency and allows for contractures without excessive lordosis.

Transfemoral sockets are set in initial adduction mainly to:

Answer: Optimize hip abductor length and reduce lateral trunk lean

Adduction positions the gluteus medius at an efficient length for pelvic stability in stance.