File:Streeter1906 plate02.jpg

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Description of Plates II

Carnegie Embryo 86 has been classified as Carnegie stage 23 occurring during Week 8, GA week 10.

The reproductions shown on this plate represents different views, lateral, front, and median, of a selected model showing the membranous labyrinth and acoustic complex reconstructed from the following human embryo No. 86, 30 mm. The drawings for Plates I and II were prepared under the guidance and assistance of Mr. Max Brodel.

The colors, yellow and red, are used to indicate respectively the cochlear and vestibular divisions, and in general nerve flbers can be distinguished from ganglion cell masses by their lighter tone. The pictures represent a magniflcation of 25 diams.

The last step in its differentiation consists in the widening of the distal end into a flattened pouch or sac, in contrast to the remainder, which persists as a narrow duct connecting it with the vestibule, indicated in Figs. a, b, c, Plate II.

The thickness of the epithelium of the outer edge and presence of division figures indicate that the activity of growth still continues. Section D shows a canal in an embryo 30 mm. long, the same stage as that shown in Figs. a, b, c, Plate II.

The initial ingrowth of the membranous partition can be seen in Figs. 1 and m, where it can be distinguished as a horizontal cleft which forms in front between the utricular and saccular parts of the atrium. Strictly speaking we cannot speak of a saccule and utricle until the intervening partition is complete. It is practically complete in Figs. a, b, c, Plate II; here it reaches back to the entrance of the ductus endolymphaticus. It later divides the orifice of that structure, thus affording it separate openings into the utricle and saccule, the two openings constituting the so-called ductus utriculo-saccularis.

  • absorpt. focus - area of wall where absorption is complete.
  • amp. - ampulla membranacea.
  • crus - crus commune.
  • - ductus semicircularis lateralis.
  • c. sc. post. - ductus semicircularis posterior.
  • c. sc. sup. - ductus semicircularis superior.
  • coch.orcochlea - ductus cochlearis.
  • duct. endolymph. - ductus endolymphaticus.
  • d. reuniens - ductus reuniens Henseni.
  • endol. or endolymph. - appendix endolymphaticus.
  • rec. utr. - recessus utriculi.
  • sacc. - sacculus.
  • sac. endol. - saccus endolymphaticus.
  • sinus utr. lat. - sinus utriculi lateralis.
  • utric. - utriculus.
  • vestib.p. - vestibular pouch.

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Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)
Mall 1906 Links: Fig 1. 14mm Embryo | Fig 2. 30mm Embryo | Fig 3. Semicircular canal | Fig 4. Membranous Labyrinth | Fig 5. Acoustic nerve complex | Fig 6. Facial-acoustic Complex | Fig 7. Facial Nerve Pig Embryo 20 cm | Fig 8. Geniculate Ganglion | Plate 1. Human Embryo 4 to 20 mm | Plate 2. Human Embryo 30 mm | Membranous Labyrinth and Nerves


Streeter GL. On the development of the membranous labyrinth and the acoustic and facial nerves in the human embryo. (1906) Amer. J Anat. 6:139-165.

Cite this page: Hill, M.A. (2024, April 22) Embryology Streeter1906 plate02.jpg. Retrieved from

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G

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