ABSTRACT
The premaxilla in man, whether exists as a separate bone or not, constitutes a "Problematic status". The incisive suture is currently described on the palate of children, while its facial representation is still unknown. Various anthropological and phylogenetic views appeared and based on the various degrees of development of both maxilla and premaxilla. The present study aims at finding a true anatomical data concerning the boundaries of premaxilla in man to compare it with its homologue in other mammals, and to correlate these fmdings with the precedent views. Serially-cut histological sections, at different planes, in human foetuses [4, 5 and 6 months] were examined. Dissection and maceration were applied on 3 other foetuses, 3 newlyborns and 8 children. Sixty macerated skulls of adult man, as well as of various mammals, were inspected for the presence of an incisive suture. The results obtained revealed a prenatal existence of premaxilla in man, on the contrary to what was claimed by Wood et aI [1967]. Also, it revealed a complete prenatal presence of an incisive suture, on palatal endonasal and facial aspects. Soon after birth, the sutural line disappeared completely on the facial aspect, and partly on endonasal one. On palatal aspect, it gradually and invariably disappeared in children and adult skulls. A nasal process of premaxilla in man was newly delineated, and constitutes the homologue of that present in mammals. In both gorilla and man, the so-called incisive process of maxilla [which overlaps premaxilla from infront] was not observed. In consequence, certain anthropological and phylogenetic views were discussed. Prognathism, duplicated narial margin etc... claimed to exist in negros and the so-called inferior human races, seemed to be in relation to the developmental and age changes The prenatal detection of the incisive suture may pave the way for a better understanding of the pathogenesis of the cleft palate