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An orthopedic cast, body cast, plaster cast, or surgical cast, is a shell, frequently made from plaster, encasing a limb (or, in some cases, large portions of the body) to stabilize and hold anatomical structures, most often a broken bone (or bones), in place until healing is confirmed. It is similar in function to a splint. Plaster bandages consist of a cotton bandage that has been combined with plaster of paris, which hardens after it has been made wet. Plaster of Paris is calcined gypsum (roasted gypsum), ground to a fine powder by milling. When water is added, the more soluble form of calcium sulfate returns to the relatively insoluble form, and heat is produced. :2 (CaSO4·½ H2O) + 3 H2O → 2 (CaSO4.2H2O) + Heat The setting of unmodified plaster starts about 10 minutes after mixing and is complete in about 45 minutes; however, the cast is not fully dry for 72 hours. Nowadays bandages of synthetic materials are often used, often knitted fiberglass bandages impregnated with polyurethane, sometimes bandages of thermoplastic. These are lighter and dry much faster than plaster bandages. However, plaster can be more easily moulded to make a snug and therefore more comfortable fit. In addition, plaster is much smoother and does not snag clothing or abrade the skin. ==History== The earliest methods of holding a reduced fracture involved using splints. These are rigid strips laid parallel to each other alongside the bone. The Ancient Egyptians used wooden splints made of bark wrapped in linen. They also used stiff bandages for support that were probably derived from embalming techniques. The use of plaster of Paris to cover walls is evident, but it seems it was never used for bandages. Ancient Hindus treated fractures with bamboo splints, and the writings of Hippocrates discuss management of fractures in some detail, recommending wooden splints plus exercise to prevent muscle atrophy during the immobilization. The ancient Greeks also used waxes and resins to create stiffened bandages and the Roman Celsus, writing in AD 30, describes how to use splints and bandages stiffened with starch. Arabian doctors used lime derived from sea shells and albumen from egg whites to stiffen bandages. The Italian School of Salerno in the twelfth century recommended bandages hardened with a flour and egg mixture as did Medieval European bonesetters, who used casts made of egg white, flour, and animal fat. By the sixteenth century the famous French surgeon Ambroise Paré (1517–1590) championed more humane treatments in medicine and promoted the use of artificial limbs made casts of wax, cardboard, cloth, and parchment that hardened as they dried. These methods all had merit, but the standard method for the healing of fractures was bed rest and restriction of activity. The search for a simpler, less-time consuming, method led to the development of the first modern occlusive dressings, stiffened at first with starch and later with plaster-of-paris. The ambulatory treatment of fractures was the direct result of these innovations. The innovation of the modern cast can be traced to, among others, four military surgeons, Dominique Jean Larrey, Louis Seutin, Antonius Mathijsen, and Nikolai Ivanovich Pirogov. Dominique Jean Larrey(1768–1842) was born in a small town in southern France. He first studied medicine with his uncle, a surgeon in Toulouse. After a short tour of duty as a naval surgeon, he returned to Paris, where he became caught up in the turmoil of the Revolution, being present at the Storming of the Bastille. From then on, he made his career as a surgeon in France's revolutionary and Napoleonic armies, which he accompanied throughout Europe and the Middle East. As a result, Larrey accumulated a vast experience of military medicine and surgery. One of his patients after the Battle of Borodino in 1812 was an infantry officer whose arm had to be amputated at the shoulder. The patient was evacuated immediately following the operation and passed from Russia, through Poland and Germany. On his arrival at his home in France the dressing was removed and the wound found to be healed. Larrey concluded that the fact that the wound had been undisturbed had facilitated healing. After the war, Larrey began stiffening bandages using camphorated alcohol, lead acetate and egg whites beaten in water. An improved method was introduced by Louis Seutin, (1793–1865) of Brussels. In 1815 Seutin had served in the allied armies in the war against Napoleon and was on the field of Waterloo. At the time of the development of his bandage he was chief surgeon in the Belgium army. Seutin’s “bandage amidonnee” consisted of cardboard splints and bandages soaked in a solution of starch and applied wet. These dressings required 2 to 3 days to dry, depending on the temperature and humidity of the surroundings. The substitution of Dextrin for starch, advocated by Velpeau, the man widely regarded as the leading French surgeon at the beginning of the 19th century, reduced the drying time to 6 hours. Although this was a vast improvement, it was still a long time, especially in the harsh environment of the battlefield. A good description of Seutin’s technique was provided by Sampson Gamgee who learned it from Seutin in France during the winter of 1851–52 and went on to promote its use in Britain. The limb was initially wrapped in wool, especially over any bony prominences. Pasteboard was then cut into shape to provide a splint and dampened down in order that it could be molded to the limb. The limb was then wrapped in bandages before a starch coating was applied to the outer surface. Seutin’s technique for the application of the starch apparatus formed the basis of the technique used with plaster of Paris dressings today. The use of this method led to the early mobilization of patients with fractures and a marked reduction in hospital time required. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Orthopedic cast」の詳細全文を読む スポンサード リンク
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