A plaster cast is a hard protective covering made from a mixture of plaster and water. It is commonly used in medicine to immobilize broken bones or injured limbs, allowing them to heal properly. Once applied, the plaster hardens and forms a rigid shell around the affected area. Plaster casts are typically used in conjunction with other medical treatments, such as X-rays to assess the injury. They can be removed after the healing process is complete, usually several weeks later. While plaster casts are effective, they can be heavy and may require care to keep them dry and clean.