This document defines key terms related to pressure ulcers such as bony prominences, shear, and friction. It explains that pressure ulcers are caused by unrelieved pressure that damages underlying tissues and lists contributing factors such as shear and friction. Persons at risk include those who are bedbound or chairbound, have impaired mobility, or have other health issues. The stages of pressure ulcers are described from initial skin discoloration to open wounds. Prevention focuses on reducing pressure and proper skin care while treatment includes wound care and pressure-reducing devices.