Health Encyclopedia

Prognathism

Definition

Prognathism is an extension of the lower jaw (mandible) that occurs when the shape of the face bones cause the teeth to be improperly lined up (misaligned).

Alternative Names

Extended chin

Considerations

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.

Common Causes

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. You can develop it as a child or adult from gigantism or acromegaly.

Home Care

It is appropriate to see a dentist or orthodontist to treat abnormal alignment of the jaw and teeth. However, also contact your primary health care provider to rule out medical disorders that can be associated with prognathism.

Call your health care provider if

There is difficulty talking, biting, or chewing related to the abnormal jaw alignment.
You have concerns about jaw alignment

What to expect at your health care provider's office

The health care provider will perform a physical examination and ask questions regarding the patient's medical history. Questions may include:

Is there any family history of an unusual jaw shape?
Is there difficulty talking, biting, or chewing?
What other symptoms do you also have?

Diagnostic tests may include:

Skull x-ray
Dental x-rays
Imprints of the bite (a plaster mold is made of the teeth)

Review Date:2/27/2008
Reviewed By:Rachel A. Lewis, MD, FAAP, Columbia University Pediatric Faculty Practice, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.