Many accounts of the human premaxilla describe its ossification centers and time of fusion with the maxilla, but that such a bone even exists in the human has long been questioned. Very few specimens undergoing initial phases of ossification have been reported and no convincing photographs of separate centers have been published. This report is based on 90 serially sectioned human embryos whose ages (Streeter's Horizons XVIII to XXIII) were closely grouped around the age when ossification of the upper jaw begins. There is but one ossification center bilaterally which, although it appears first in the cuspid region, rapidly involves an area extending from the molar to the central incisor region.Not one of the specimens showed an independent center for the "premaxilIa" nor an "incisive suture" in the area of ossification. The premaxilla does not exist as an independent bone in man.Differing views concerning ossification centers of the anterior upper jaw (premaxilla) in man appear in the literature. Chase ('42) summarizes the views of a number of European investigators. He relates that Kollicker, Schwick, Mall, Brune, Inouye and Felber all contend that there is one center bilaterally for the premaxilla; Leuckhard, Albrecht, Biondi, Herbst, and Federspiel that there are two; and that Peter, Jarmer, Callender, Rambaud and Renault describe even more centers. Chase ('42) and Kraus and Decker ('60), identified one; Woo ('49) two; and Shepherd and McCarthy ('55) three centers bilaterally. However several of these authors remark that the separateness of centers was difficult to see, and that, after their appearance, fusion was rapid.Only two photographs have been published purporting to show separate ossification centers for the premaxilla, but neither is convincing. Both photographs are of alizarin-stained specimens. One (Woo, '49) appears to be a dissected specimen, and the other (Kraus and Decker, '60) is of an intact specimen but it is the labelling and not the picture which indicates separate centers.Not only is the number of ossification centers disputed, but the very existence ANAT. REC., 158. 485-490. of a premaxilla in man has been doubted. Fawcett ('ll), Frazer ('16), Jacobsen ('53), and Zimmerman ('66) were unable to demonstrate the existence of a separate premaxillary ossification center.Most reports are based on very few specimens, in early stages of ossification. We therefore restudied the development of the premaxilla in man using a large number of well preserved specimensall close to the age when its ossification begins (ovulation age ca. 40
