Broken bones need time and stillness to knit. A cast is a rigid external dressing, traditionally made of plaster or fiberglass, that immobilizes a fractured bone or injured joint while healing occurs.

After reduction of the fracture, padding is applied and the casting material is molded to maintain alignment. The cast must be tight enough for support yet loose enough to allow circulation. Patients receive instructions about elevation, warning signs of tightness, and keeping the cast dry.

Follow-up radiographs confirm that position is maintained. Casts are removed with oscillating saws once healing is adequate. Complications include pressure sores, stiffness, and, rarely, compartment syndrome if swelling is underestimated. Proper application and patient education prevent most problems.

• Rigid dressing that immobilizes a fracture or joint
• Made of plaster or synthetic materials
• Maintains alignment during bone healing
• Requires monitoring for circulation and skin problems