Benign hypertrophy of the mandibular angle of the chewing muscle is a common facial deformity in the Oriental population. The facial shape in this group is often wind-shaped and use-shaped. The lower third of the face is significantly wider. In severe cases, the mandibular angle protrudes backward and downward, and some are accompanied by shortening of the lower third of the face. Patients have visible or palpable hypertrophic bulging chewing muscle strips when biting. Most of the cases are bilateral, but a few are unilateral. Left-right asymmetry is also common in bilateral cases, while unilateral asymmetry is very pronounced. Most patients have no significant discomfort.