Both fiberglass and plaster splints and casts use padding, usually cotton, as a protective layer next to the skin.
Both materials come in strips or rolls which are dipped in water and applied over the padding covering the injured area.
The splint or cast must fit the shape of the injured arm or leg correctly to provide the best possible support.
In many cases, a splint is applied to a fresh injury first.
As swelling subsides, a full cast may replace the splint.
Sometimes, it may be necessary to replace a cast as swelling goes down and the cast gets “too big.” As a fracture heals, the cast may be replaced by a splint to make it easier to perform physical therapy exercises.