The plan of the human face: a test of three general concepts.

In The Handbook of Facial Growth, Enlow proposes a series of anatomic concepts that account for "the plan of the human face." Three of those concepts are examined in this article, which presents measurements of 253 adult female primates from thirty-two species. As part of a system of craniofacial counterparts, Enlow proposes that the breadth of the mandibular ramus should equal the breadth of the pharynx. The relationship between ramus breadth and PNS-Ba in the primates studied strongly supports this hypothesis. A second concept tested concerns the relationship between prognathism and maxillary arch length. The relationship is not as strong as in the previous case, and some species are more prognathic than required for the size of their dentition. It is concluded that arch length and prognathism have an important biologic relationship but that the two features can vary with some independence. The third concept tested is the relationship between prognathism and interorbital breadth. Here the relationship is weak, and it is concluded that the interorbital breadth is not significant in setting a structural limit to the amount of facial prognathism.