What Are Casts Made Of?

Casts are custom-made and applied by a doctor or a medical assistant. A cast consists of two parts, a hard outer shell, and a soft lining which is next to the skin.

Purpose of a Cast

• Doctors apply casts to facilitate proper healing of broken bones. Patients who require immobilization following certain surgeries may also need casts.

Plaster Casts

• Some casts are made of plaster of paris, a heavy white powder which, when mixed with water, forms a thick paste which quickly dries hard.

Fiberglass Casts

• Fiberglass, a kind of plastic which can be molded, is used to make casts which are lighter and stronger than plaster casts. Fiberglass casts come a variety of colors, says KidsHealth.org.

Lining

• Both kinds of casts are placed over a layer of soft padding that goes next to the skin. To avoid rash and infection, patients with cotton and synthetic lining must take precautions that their casts stay dry.

Waterproof Casts

• A new kind of lining is one made from GORE-TEX. In combination with a fiberglass cast, GORE-TEX dries quickly and can safely be immersed in water, according to the Center for Orthopaedics and Sports Medicine.