A text-book of dental histology and embryology, including laboratory directions . r arch there isleft an almost cubical space between the lower surface ofthe fore- and midbrain and the upper surface of the mandib-ular arch (Fig. 271). This is a part of the outside world,and is enclosed to form the mouth and nose cavities. Thisprocess is best understood if we think of the developmentfrom the anterior end of the forebrain of a process whichmay be described as a curtain dropping down, making acentral piece, and the bud from the mandibular arch on eachside growing forward to unite with it, leaving
A text-book of dental histology and embryology, including laboratory directions . r arch there isleft an almost cubical space between the lower surface ofthe fore- and midbrain and the upper surface of the mandib-ular arch (Fig. 271). This is a part of the outside world,and is enclosed to form the mouth and nose cavities. Thisprocess is best understood if we think of the developmentfrom the anterior end of the forebrain of a process whichmay be described as a curtain dropping down, making acentral piece, and the bud from the mandibular arch on eachside growing forward to unite with it, leaving a slit betweenthem and the mandibular arch which will be the mouth. Inorder to get a correct idea of this process it must be followedsomewhat more minutely. Frontonasal Process.—As the frontonasal process developsit is made up of four rather bulk-like portions (Figs. 272 and273), two occupying the centre and which develop into the 358 Lens. Olfactorypit. EARLY STAGES OF EMBRYOLOGYFig. 272 Maxillary process. Mandibular arch. Hyo-mandibular cleft. Auditory ?hyoid arch Sinus -*? praecervicahs y The beginning of the mandibular arch and the maxillary 273Cerebral hemisphere. J Fronto-nasalprocess. Stomodseum.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectteeth, bookyear1912
