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).

Extended chin

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.

It may develop over time in children or adults as the result of conditions such as gigantism or acromegaly.

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Prognathism

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Prognathism Treatment

Review Date: 01/28/2010
Reviewed By: Kimberly G. Lee, MD, MSc, IBCLC, Associate Professor of Pediatrics, Division of Neonatology, Medical University of Charleston, SC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)