Prognathism

A chimpanzee skull: the jaws stick out in front this causes a prognathic face.

A human skull: the normal human face is basically vertical this causes an orthognathic face.

Prognathism describes when part or all of the face sticks out more than normal. Humans have orthognathic faces. That means the faces is more or less vertical. Most other primates have prognathic faces: their jaws stick out in front of the top part of the head.

Mandibular prognathism is when the lower jaw sticks out.

• Nasal prognathism: is when the portion of the face around and including the nose sticks out. Also called upper facial projection.

• Alveolar prognathism: is when the alveolar (dental) part of the upper jaw (maxilla) sticks out. Also called mid-facial projection. Often causes what is called an "overbite".

• Mandibular prognathism: is when the mandible (lower jaw) sticks out. Often called an "underbite".

Prognathism Media

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  Mandibular prognathism, where teeth have almost reached their final, straight position by dental braces. This makes the prognathism more obvious, and it will take an operation, moving the jaw backwards, to give the ultimate result.

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  Alveolar prognathism, caused by thumb sucking and tongue thrusting in a seven-year-old girl.

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  Leopold I, showing progenism