マウス上顎骨の発生学的研究
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概要
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A histogenetic study of the maxillar bone including premaxillary was conducted on the embryo, weanling and adult of normal healthy mice as materials. 1. The development of the anlages : at the 14 or 15th embryonic day there are observed an anlage of the premaxillary lying on the dorsal side of the incisor's dental lamina, and also, located backward, two anlages of maxilla, the one lying inside, the other outside of ventral side of the maxillary nerve, or to say otherwise, each one inside and outside of dorsal side of the dental lamina of molar teeth. 2. The time of ossification : at the 15th embryonic day the middle cores of these bone anlages have already gone into ossification, and one observes there 3 slim fragments of bone newly formed, one in the premaxillary and two in the maxilla. 3. Formation and completion of the general contour : the general contour of the maxilla is outlined by the 17th embryonic day, and with the perfection of periostium at the 7th post-natal day, the morphological and histological details become nearly integrated, eventually reaching to completion of the bone by approximately 30 days post-natally when the 3rd molar tooth makes its appearance. 4. Completion of the infraorbital foramen The general contour of the infraoroital foramen is accomplished primarily by fusion of the processus frontalis and the processus premaxillaris by the 18th embryonic day, and its approximate completion is brought about by the 5th postnatal day by means of collateral development of the two processes and the posterior portion of the bodies of the respective bone, together with development of the lacrimal bone. 5. Completion of the incisal canal In the fetus of the 16th day, there start to develop the palatine process in the premaxillary and the palatine spine in the maxilla, and by the 21th fetal day the two processes come to fuse dorso-ventrally at the vicinity of anterior margin of the orbit to complete the incisal canal. 6. The nasolacrimal duct : the duct, arising from the lacrimal sac, is not allowed to get its outlet until the 15th embryonic day with its closed and located at the neiborhood of outer ventral side of the lateral nasal cartilage. By the 16th embryonic day it opens for the first time in front of the primary nose of the animal. 7. The naso-palatine and the palatine cartilages : at the 18th day of the fetus, condensation of the mesenchymal cells is observed to form the anlages of the palatine and nasopalatine cartilages of which the former is converted into hyaline cartilage at the first natal day, the latter at the second natal day. The palatine cartilages on both sides come to be united by the connective tissue union at the 3rd embryonic day, followed by the cartilage union at approximately the 20th embryonic day.
- 九州歯科学会の論文
- 1958-06-30