Pressure ulcers, also known as bedsores or decubitus ulcers, are injuries to the skin and underlying tissue that occur when there is prolonged pressure on the skin. They commonly develop in areas where bones are close to the skin, such as the heels, elbows, and sacrum. Factors like immobility, poor nutrition, and moisture can increase the risk of developing these ulcers. These ulcers are classified into different stages based on their severity, ranging from mild redness to deep wounds that expose muscle or bone. Prevention strategies include regular repositioning, maintaining skin hygiene, and using specialized mattresses or cushions to relieve pressure.