Jaw abnormality sagittally divides the face into five equal parts: It is insufficient to derive at a diagnosis of jaw deformity solely based on the clinical examination. Hence, additional information is gathered from diagnostic tests, which may include dental model analyses and radiographic imaging studies. Mandibular micrognathia is the condition when lower jaw is smaller than normal. Failure of the ramus to develop will give rise to micrognathia.<ref name="Elsevier/Churchill Livingstone"></ref> Micrognathia can be classified as either congenital or acquired. Clinical appearance of some patients with congenital type of mandibular micrognathia can have a severe retrusion of the chin but by actual measurements,
Jaw abnormality has an "abnormal roll", a condition also known as "cant". Finally, when a jaw is malrotated around the vertical axis, it has "abnormal yaw". It can occur in maxilla and/or mandible and could result due to abnormal growth of the jaws in itself or as compensatory growth. "Shape" refers to figure, the geometric characteristic of an object that is not size, position, or orientation . A jaw with abnormal shape is said be "distorted". Completeness means the wholeness of the jaw. When failure of tissues to fuse together that are forming early in pregnancy, defect can happen and jaw is