Orthopedic cast

A cast is a shell, frequently made from plaster, encasing a limb (or, in some cases, large portions of the body) to hold a broken bone (or bones) in place until it has healed.

Real plaster bandages contain plaster of paris, which hardens out after it has been made wet due to a chemical reaction. Nowadays fiberglass is often used instead of plaster as it is lighter and dries faster. However, real plaster can be more easily moulded to make a snug and therefore more comfortable fit. In addition, real plaster is much smoother and does not snag clothing or abrade the skin. Plaster casts are generally made available only to patients who insist on them because they take more time to apply.

Casts may be grouped into the following categories:

Upper Extremity Casts

Upper Extremity Casts are those which encase the arm, wrist, and/or hand. A long arm cast encases the arm from the hand to the elbow, leaving the fingers and thumbs free. A short arm cast, in contrast, stops just below the elbow. Both varieties may, depending on the injury and the doctor's decision, include one or more fingers or the thumb, in which case it is called a finger spica or thumb spica cast.

Lower Extremity Casts

Lower Extremity Casts are classified similarly, with a cast encasing both the foot and the leg to the hip being called a long leg cast, while one covering only the foot and the lower leg is called a short leg cast. A walking heel may be applied, as in the photo at right, or a canvas or leather cast shoe provided to the patient who is expected to walk on the immobilized limb during convelescence (referred to as being weight bearing). Where the patient is not to walk on the injured limb, crutches or a wheelchair may be provided. The sole of a leg cast may also be extrended to the tip of the toes, providing a toeplate. This addition may be made to offer support to and stabalize the metatarsals and to protect the toes from additional trauma. Toeplates are infrequently used in the USA, and are more common in Europe.

Cylinder cast

In some cases, a cast may include the upper and lower arm and the elbow, but leave the wrist and hand free, or the upper and lower leg and the knee, leaving the foot and ankle free. Such a cast may be called a cylinder cast, or may simply be called a long arm or long leg cast.

Body casts

Body casts, which cover the trunk of the body, and in some cases the neck up to or including the head or one or more limbs, are rarely used today, and are most commonly used in the cases of small children, which cannot be trusted to comply with a brace, or in cases of radical surgery to repair an injury or other defect. A body cast which encases the trunk of the body from the hips to the armpits (which may or may not include "straps" over the shoulders), is usually referred to as a body jacket.

Spica cast

A cast which includes the trunk of the body and one or more limbs is called a spica cast, just as a cast which includes the "trunk" of the arm and one or more fingers or the thumb is. For example, a shoulder spica includes the trunk of the body and one arm, usually to the wrist or hand. Shoulder spicas are almost never seen today, having been replaced with specialized splints and slings which allow early mobility of the injury so as to avoid joint stiffness after healing.

A hip spica includes the trunk of the body and one or more legs. A hip spica which covers only one leg to the ankle or foot may be referred to as a single hip spica, while one which covers both legs is called a double hip spica. A one-and-a-half hip spica encases one leg to the ankle or foot and the other to just above the knee. The extent to which the hip spica covers the trunk depends greatly on the injury and the surgeon; the spica may extend only to the navel, allowing mobility of the spine and the possibility of walking with the aid of crutches, or may extend to the rib cage or even to the armpits in some rare cases. Hip spicas were formerly common in reducing femoral fractures, but today are rarely used except for congenital hip locations, and then mostly while the child is still an infant.

In some cases, a hip spica may only extend down one or more legs to above the knee. Such casts, called pantaloon casts, are occasionally seen to immobilize an injured lumbar spine or pelvis, in which case the trunk portion of the cast usually extends to the armpits.

Other casts

Other body casts which were used in decades past to protect an injured spine or as part of the treatment for a spinal deformity (see scoliosis) which are rarely seen today include the Minerva cast and Risser cast. The Minerva cast includes the trunk of the body (sometimes extending down only so far as the rib cage) as well as the patient's head, with openings provided for the patient's face, ears, and usually the top of the head and hair. The Risser cast was similar, extending from the patient's hips to the neck and sometimes including part of the head. Both of these casts could, with care and the doctor's permission, be walked in during convelescence. However, in some cases the Risser cast would extend into one or more pantaloons, in which case mobility was far more restricted.

Aside from the above common forms, body casts could come in nearly any size and configuration. For example, from the 1910s to the 1970s, use of a turnbuckle cast, which used metal turnbuckles to twist two halves of the cast so as to forcibly straighten the spine before surgery, was common. The turnbuckle cast had no single configuration, and could be as small as a body jacket split in half, or could include the head, one or both legs to the knees or feet, and/or one arm to the elbow or wrist depending on the whim of the doctor.

Despite the large size and extreme immobilization some casts, particularly those used in or before the 1970s, the popular term full body cast is something of a misnomer. The popular and media-driven conception of a massive cast encasing all four limbs, the trunk, and the head--sometimes leaving only small slits for the eyes, nose, and mouth--has no parallel in recorded medical history. The term is loosely used by laymen to describe any of a number of body and or spica casts, from a simple body jacket to a more extensive hip spica.

orthopedics