There are two possible reasons for the sunken sides of a woman’s buttocks. The first one is due to the corresponding decrease of subcutaneous fat as women age, and the buttocks appear less full than before due to the decrease of fat, and depressions can appear under the outer part of the gluteus maximus muscle, mostly without special treatment. The second cause may be caused by gluteus contracture, which may be related to muscle atrophy caused by excessive local muscle injections, and is characterized by a characteristic gait, walking with an outward-looking, swaying gait.