ABNORMAL CONDITIONS OF TILE BONES OF THE FACE.
In the true acephalous fetus the bones of the face as well as those of the cranium are of course wanting, but the former are generally found in what are termed the false Acephalia (see ABNORMAL CONDITIONS OF THE CRANIUM); it sometimes happens, not withstanding, that the bones of the face are but imperfectly developed, presenting a variety of conformations which it is unnecessary to parti cularise. The bones of the face, in some cases alone, and in others in conjunction with those of the cranium, not unfrequently Requite a de gree of development quite disproportionate with the rest of the skeleton. In Corvisart's Journal de Medecine the case of a Moor is cited, whose head and face were so enormous that he could not stir abroad without being followed by the populace. It is related that the nose of this man, who was half an idiot, was four inches long, and his mouth so large that he would bite a melon in the proportion that an ordinary per son would eat an apple. I have now before me the skull of a native of Shields, who was remarkable during life for the length of his face ; the entire head is large, but the bones of the face, and particularly the lower jaw, are enormously long. The abnormal development of the facial bones generally affects one jaw only, and more frequently the lower, as in the example just mentioned. Other cases, but they are much more rare, have been related in which the lower jaw was disproportionately small. When, from either of the circumstances which have been just mentioned, the develop ment of the two jaws is unequal, the corre spondence of their alveolar borders is lost, and mastication becomes in proportion imperfect : in mammifcrous animals the unequal size of the lower jaw, by preventing suckling, is often a cause of death. The bones of the face are much more symmetrical than those of the cra nium, and rarely present the disproportion in their lateral development which is observed in the latter.
Under the head of defect or arrest of deve lopment may be noticed, 1. the occasional ab sence of some of the bones, as for example, the lachrymal or the vomer; 2. the existence of fissures, or non-union of the upper maxillary bones, and, as a more rare case, the separation of the two halves of the lower jaw. Fissures of the upper jaw may exist in various degrees, and may occur with or without a corresponding cleft in the soft palate and lip ; it may appear as a mere slit along the middle of the roof of the mouth, forming a narrow communication between that cavity and one side of the nose ; or it may extend along the whole of the pala tine arch, and be continuous behind with a similar division of the soft palate, without, at the same time, being accompanied with hare lip. Sometimes the aperture is very wide, and the palatine plates of the upper maxillary and palate bones are almost entirely wanting ; in this case the vomer and middle cartilage of the nose are also partially or entirely absent; and there is both hare-lip and cleft of the soft palate, so that the mouth, both sides of the nose, and the pharynx are laid into one great cavity. When the fissure exists at the anterior part of the palate only, it almost invariably occurs at the suture which has been described between the maxillary and intermaxillary bones, so that the cleft separates the canine from the lateral incisor tooth ; when the fissure occurs on both sides of the face, the four incisor teeth are separated from the others and lodged in an alveolar border, which usually in this case projects more or less towards the lip, in which there is also commonly a single or double cleft or hare-lip. Sometimes the fissure occurs in the intermaxillary bone itself between the lateral and middle incisor teeth, and then we find a single incisor on one side and three on the op posite : it is very rarely that the cleft exists in the median line between the two intermaxillary bones.