What is a square face?

A square face, also known as masseter hypertrophy or prominent jaw angle, refers to a condition where the lower sides of the face (commonly referred to as the jawline area, just below the ears) protrude noticeably. When viewed from the front, the sides of the face form vertical lines that meet the lower jaw at nearly right angles, making the lower face appear wide and broad.

Medically, the primary cause is overdevelopment of the mandibular angle bone, enlargement of the masseter muscles, or a combination of both. This is often related to habits such as frequent snacking, chewing gum or betel nut, or teeth grinding during sleep—all of which can overwork the jaw muscles, stimulating both bone and muscle growth.