The strength of the muscles above the joint is critical in choosing componentry. Less strong muscles may need components that provide stability while stronger muscles may allow components which maximize functionality. After visual inspection the prosthetist takes measurements of the residual limb. Length, circumferences, joint measurements, range of motion, shoe size, and a variety of data are taken and recorded. A good prosthetist takes time to record these measurements accurately and may repeat this procedure several times.
Impression Taking Creating the socket is one of the most crucial steps in making the prosthesis.
Socket geometry not only dictates comfort, but must also provide support and surfaces necessary for weight transfer. The socket must transfer body weight onto load bearing areas and provide relief space for bony or sensitive areas. The socket does not perfectly match the shape of the residual limb because of its special modifications to allow loading and unloading. Creating the socket or socket interface begins with taking an impression of the residual limb, usually done with plaster gauze like that used for fracture casts. The difference is that the prosthetic cast not only follows the limb contours, but is intentionally modified to push into weight tolerant areas and relieve intolerant areas.