Pressure sores occur in people who are bedridden or have limited mobility, and are mostly found in areas with prominent bones. The long-term pressure on the local tissues of the body leads to impaired blood circulation, which often results in ulcers, blisters, and even rotting flesh. The local skin may also appear as a lump, hard or soft to the touch, and may be accompanied by pain, and the local skin temperature may also change; 2. Stage II pressure ulcers: the inflammatory infiltrative stage, in which the local skin is seen to break down and ulcers or blisters are formed, and the blisters are filled with pus; 3. Stage III pressure ulcers: the superficial ulcer stage, in which the injury has reached the deeper layers of the skin and the subcutaneous fat can be seen from the wound, but the muscles, tendons, and bones, etc. are not yet exposed. At this stage, the injury has reached the deeper layers of the skin and the subcutaneous fat is visible, but the muscles, tendons, bones, etc. are not yet exposed. The wound may also be complicated by osteomyelitis, with symptoms such as generalized high fever, chills, pus flowing from the diseased bones, fractures and bone fragments being discharged. The specific depth cannot be determined, and rotting flesh and scabs may appear at the bottom of the wound; 6. Suspected deep tissue injury stage pressure sores: the specific depth is unknown, and deep tissue is exposed. Purple or maroon spots, congested blisters, pain, erosion, changes in skin temperature, hard nodes and interspersed distribution of loose and soft tissues appear on the lesioned skin.