Bedsores (pressure ulcers) – Symptoms and causes – Mayo Clinic

Bedsores are areas of damaged skin and tissue caused by sustained pressure — often from a bed or wheelchair — that reduces blood circulation to vulnerable areas of the body. Bedsores — also called pressure ulcers and decubitus ulcers — are injuries to skin and underlying tissue resulting from prolonged pressure on the skin.

https://www.mayoclinic.org/diseases-conditions/bed-sores/symptoms-causes/syc-20355893