Prognathism is an extension or bulging out (protrusion) of the lower jaw (mandible) that occurs when the shape of the face bones cause the teeth to be improperly lined up (misaligned).
Prognathism may cause malocclusion (misalignment of the biting surfaces of the upper and lower teeth), giving some people an angry, or fighter's, appearance. Prognathism may be a symptom of various syndromes or conditions.
An extended (protruding) jaw can be part of the normal facial shape a person is born with.
It can also be caused by inherited conditions such as Crouzon syndrome or basal cell nevus syndrome.
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