Hip protrusion. Inquired by Sanjiu Yangshengtang, hip pressure sores mainly occur in the femoral trochanter, ischial tubercle and other bony processes. Because of the large contact surface between hip bony processes and stool, there are many frictions, which can also be seen in other friction parts. Pressure ulcer, also known as bedsore and pressure ulcer, is caused by long-term pressure on local skin of the body, which affects blood circulation, leading to nutritional deficiency and damage of skin and subcutaneous tissue, and even ulcer and necrosis. It often occurs in the protruding part of compressed bone.