The most common reasons for the formation of bite muscle hypertrophy are two: 1, genetic factors: and genetics have a certain relationship, especially the degree of facial skeletal symmetry bite muscle hypertrophy, is related to the genetic constitution, and parents tend to look the same facial appearance, genetic factors can not be ignored; 2, non-genetic factors: some patients with bite muscle hypertrophy parents do not exist in such a situation, may be due to long-term chewing habits Poor, lateral chewing, malnutrition, or local bite muscle after exercise caused by, called work hypertrophy. Non-genetic factors cause hypertrophy of the bite muscle, most of them are lateral hypertrophy, and there are relatively few symmetrical hypertrophy on both sides.