A pressure ulcer forms when a resident is left in one position long enough for the blood supply to the skin to be cut off. Facilities know this. That is why care plans call for repositioning at least every two hours, daily skin checks, adequate nutrition and hydration, and pressure-relieving surfaces. Federal nursing home regulations require a facility to prevent pressure ulcers unless they were clinically unavoidable. When a wound reaches stage 3 or stage 4, the question is almost never whether something went wrong. It is who let it.