The development of the human body; a manual of human embryology . mbryo of mm. A short distance below the level at which the canals communicate with the re-maining portion of the oto-cyst a constriction appears,indicating a separation of theotocyst into a more dorsalportion, which becomes theutriculus, and a more ventralone. Later, the ventral por-tion of the latter begins to beprolonged into a flattenedcanal which, as it elongates,becomes coiled upon itselfand also becomes separatedby a constriction from theportion of the otocyst fromwhich it arises. The latter isthe representative of th
The development of the human body; a manual of human embryology . mbryo of mm. A short distance below the level at which the canals communicate with the re-maining portion of the oto-cyst a constriction appears,indicating a separation of theotocyst into a more dorsalportion, which becomes theutriculus, and a more ventralone. Later, the ventral por-tion of the latter begins to beprolonged into a flattenedcanal which, as it elongates,becomes coiled upon itselfand also becomes separatedby a constriction from theportion of the otocyst fromwhich it arises. The latter isthe representative of theadult sacculus (Fig. 243, s),while the coiled canal (co)forms the scala media of thecochlea and the constrictedportion of the otocyst, whichunites the scala and the sac-culus, becomes the canalisreuniens. The constrictionwhich marks the line of sep-aration of the utriculus (ut) and sacculus is convertedinto a narrow canal with which the ductus endolymph-aticus connects, and hence it is that, in the adult, theconnection between these two portions of the otocyst. Fig. 242.—Reconstruction op the Otocyst of an Embryo of , Cochlea; de, endolymphatic duct; sc, semicircular canal. —(.His, Jr.) THE INTERNAL EAR. 463 seems to be formed by the ductus dividing proximallyinto two limbs, one of which is connected with the utri-cle and the other with the saccule. When first observed in the human embryo the auditoryganglion is closely associated with the geniculate ganglionof the seventh nerve (Fig. 241, B), the two, usuallyspoken of as the acustico-facialis ganglion, forming a mass
Size: 1060px × 2357px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
