Q18: Other congenital malformations of face and neck

Q18.4: Macrostomia

An elongated mouth aperture is caused by a cleft forming between the soft tissues of the upper jaw and lower jaw. While developing, during pregnancy, the soft tissues of the upper jaw and lower jaw grow towards each other. When they are adjacent to each other, they merge. The mouth aperture remains as the opening between the two areas. If the soft tissues of the upper jaw and lower jaw do not merge properly, the mouth aperture may be elongated. An elongated mouth aperture can extend more or less deeply into the layers of tissue. The cleft may only affect the skin. The underlying muscles may also be affected. The cleft may also extend through all the layers of tissue.