Positive Model
A plaster, foam, or digitally milled replica of the residual limb, used as the forming surface over which a prosthetic socket is fabricated.
Full Definition
The positive model (also called a positive cast or positive mould) is derived from a negative cast of the residual limb or from a digital scan. The prosthetist modifies the positive model by adding or removing material at key anatomical landmarks to achieve the desired pressure distribution before the socket is thermoformed or laminated over it. Editors should distinguish 'positive model' from 'negative cast' — the negative cast is the hollow impression taken directly from the limb, while the positive model is the solid replica produced from it. Both terms appear in fabrication records and should be used precisely.
Usage
Usage note: 'Positive model,' 'positive cast,' and 'positive mould' are interchangeable but editors should preserve the author's chosen term for consistency within a document.
In Context
- "The prosthetist added plaster to the positive model over the fibular head to provide pressure relief in the finished socket." — Prosthetic fabrication record
- "An editor reviewing CAD/CAM prosthetic records should understand that a 'digital positive model' fulfils the same function as a plaster positive cast." — Editorial training note