There are several common reasons why there is no meat on the buttocks: first, gluteal myoclonus, the clinical manifestations of hip joint activities with popping, squatting obstacles, gait abnormalities, external eights, fast running with jumping signs, and easy to fall, sitting position, the lower limbs can not be in front of the knee cross, can not be cocked legs. Examination reveals atrophy of the gluteal muscle on the affected side, and a tough cord that runs in line with the gluteal muscle can be detected. Sitting or standing when the two knee joints can not be together, squatting when the two hip joints were abducted, external rotation posture, the two knee joints are separated, when squatting when the two hip joints are flexed nearly 90 degrees when the hip flexion is blocked, the whole squatting is limited, at this time the two hip and knee joints flashing outward, and then quickly close together, rowing a semicircular arc, to complete the deep squatting; secondly, suffering from diabetes mellitus and other consumptive diseases, resulting in gluteal muscular malnutrition gluteal muscle atrophy.