In connection with the vertical position of the body, such mechanical forces as body weight, viscera, intra-abdominal pressure, traction of muscles, tendons and ligament apparatus act on the human pelvis. The bone structures - the internal plates of the spongy substance and the end plates of the compact substance, the highest concentration of which occurs at the sites of compression and tension - are modeled under the influence of these forces. The aforementioned places of increased bone density in the composition of the bone pelvis are its buttresses. The connecting foundation of the buttress system of the pelvis is the sacrum, perceiving the effects of mechanical forces and transmitting them to the pelvic bones. The authors distinguished the following bone buttresses: 1 - lumbo-sacral-iliac-femoral; 2 - lumbo-sacral-iliac-sciatic; 3 - sacro-sciatic; 4 - sacro-femoral; 5 - sacro-iliac-pubical. It is necessary to consider buttresses of the pelvis from the position of arched structures, with the obligatory int