File:Streeter1917-fig08.jpg

Figure 8 and 9. Lateral Views of left membranous labyrinth human fetus 130 mm

Lateral view of a wax-plate reconstruction of the left membranous labyrinth and the periotic spaces in a human fetus, 130 mm. CR length (Carnegie Collection, No. 1018) enlarged 9 diameters. The cartilagenous stapes was removed from this model and the oval impression that it makes on the cistern can be plainly seen. The cistern has spread over the top of the utricle and along the lateral canal. The scala vestibuli extends to the tip of the cochlear duct where it communicates with the scala tympani, thus forming the helicotrema.

At this time the periotic cistern has spread over the vestibular part of the membranous labyrinth, covering it nearly everywhere excepting at the macular portions where the nerves terminate. In figure 9 it can be seen that the mesial surface of the saccule is not covered; this lies closely against the wall of the cartilagenous vestibule. The uppermost division of the cistern situated between the crus commune and the ampulla of the posterior canal does not yet open into the general cavity. It has formed separately and owing to the position in which it lies its coalescence with the other parts of the cistern is retarded. Otherwise free communication exists between all divisions of the cistern.

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Reference

Streeter GL. The development of the scala tympani, scala vestibuli and perioticular cistern in the human embryo. (1917) Amer. J Anat. 21: 300-320.

Cite this page: Hill, M.A. (2024, April 26) Embryology Streeter1917-fig08.jpg. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/File:Streeter1917-fig08.jpg

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