Physicians are infrequently asked to evaluate an individual with facial disfigurement following an injury because, when the face is injured, typically it heals without any ratable impairment. When a permanent facial disfigurement must be rated, physicians can use Section 9.2 of the AMA Guides to the Evaluation of Permanent Impairment ( AMA Guides ). Chapter 9 of the AMA Guides is unique because it deals only with permanent impairment related to the face's structural integrity, which may be only one aspect of a patient's condition that requires an impairment rating. Facial disfigurement may be the result of a complicated process, for example, a burn that involves multiple organ systems, each with a loss of function that requires an impairment rating. These ratings fall into one of four classes: Class 1 is used when the disorder is limited to the cutaneous structures and may involve a scar or abnormal pigmentation in the cutaneous structures of the face. Class 2 involves loss of some significant underlying supporting structure of the face without significant functional loss or major disfigurement such as a depressed orbital rim, frontal bone, or nasal bone. Class 3 indicates loss of a normal anatomic part or area of the face, eg, an eye. A facial disfigurement so severe that it precludes social acceptance is a Class 4 impairment.