What's the name of the bone in your ass?

What is the name of the bone on the buttocks? The bone above the buttocks is the rear of the ilium, which is the ilium. The muscle attachment point of the buttocks is compounded on this ilium. The ilium is the pelvis, and there are two ilium bones on each side of the pelvis. The belt is the anterior superior iliac spine, followed by the ilium and the posterior superior iliac spine. The ilium attached to the buttock muscle is further to the middle of the sacrum and coccyx, which are connected to the ilium. This place has two sides, each with a sacroiliac joint. This sacroiliac joint is an important joint connecting the pelvis and the spine. There are many ligaments on the sacroiliac joint in this place, and some muscles attach to this place. During exercise, it will cause damage to the sacroiliac joint and show pain. The sacroiliac joint is also the most prone position for ankylosing spondylitis, which may show signs of initial soreness, difficulty, discomfort, etc. Therefore, the bones above the buttocks are mainly the ilium, and then the ilium is the sacrum and coccyx in the middle, and then the lumbar spine is the anatomical structure of the bones.