The development of the human body; a manual of human embryology . s indicated by the transverse lines; that of the ninth by the oblique lines; and that of the tenth by the small circles.—(Zander.) seventh. There seems, however, to have been a dislocationforward, if it may be so expressed, of the mucous membrane,the sensory distribution of the ninth nerve extending forwardupon the posterior part of the anterior portion of the tongue, THE SALIVARY GLANDS. 309 while a considerable portion of the posterior portion is suppliedby the tenth nerve. The distribution of the sensory fibers ofthe facial i
The development of the human body; a manual of human embryology . s indicated by the transverse lines; that of the ninth by the oblique lines; and that of the tenth by the small circles.—(Zander.) seventh. There seems, however, to have been a dislocationforward, if it may be so expressed, of the mucous membrane,the sensory distribution of the ninth nerve extending forwardupon the posterior part of the anterior portion of the tongue, THE SALIVARY GLANDS. 309 while a considerable portion of the posterior portion is suppliedby the tenth nerve. The distribution of the sensory fibers ofthe facial is probably confined entirely to the anterior portion,though further information is needed to determine the exactdistribution of both the motor and sensory fibers of this nerve inthe tongue. The Development of the Salivary Glands.—In embryosof about 8 mm. a slight furrow may be observed in thefloor of the groove which connects the lip grooves of theupper and lower jaws at the angle of the mouth and maybe known as the cheek groove. In later stages this furrow. CW X/l S/n Fig. 163.—An Oblique Section through the Mouth Cavity of anEmbryo op about 16 to 17 mm. cm, Meckels cartilage; id, inferior dental nerve; nl, lingual nerve; P, parotidgland; SL, septum of the tongue; si, sublingual gland; sm, submaxil-lary gland; t, tooth; XII, hypoglossal nerve.—(His.) deepens and eventually becomes closed in to form a hol-low tubular structure, which in embryos of 17 mm. hasseparated from the epithelium of the floor of the cheekgroove except at its anterior end and has become em-bedded in the connective tissue of the cheek. This tubeis readily recognizable as the parotid gland and Stensonsduct, and from the latter as it passes across the massetermuscle a pouch-like outgrowth is early formed whichprobably represents the socia parotides. The submaxillary gland and Whartons duct appear in 3IO THE DEVELOPMENT OF THE HUMAN BODY. embryos of about 13 mm. as a longitudinal ridge-likethickening
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
