Category:Carnegie Embryo 584a

This Embryology category includes pages and images that relate to the Carnegie Collection Embryo No. {{CE584a}.

References

Kunitomo K. The development and reduction of the tail and of the caudal end of the spinal cord (1920) Contrib. Embryol., Carnegie Inst. Wash. Publ. 272, 9: 163-198.

Embryo No. 584a, 2.5 mm Crown-Rump Length

A profile reconstruction of the caudal end of embryo No. {{CE584a} is shown in figure 42 and a simplified sketch is shown in figure 17. There are 34 vertebrae, the last being larger than the thirty-third. Around the cartilaginous mid-portion of the last vertebra there is considerable pre-cartilaginous tissue, which has been formed by the fusion of several scleromeres. At the thirty-first and thirty-second vertebrae the column curves ventrally. The chorda dorsalis makes a loop in the thirty-fourth vertebra and gives off short branches. The central canal narrows sharply at the level of the thirty-second vertebra, but expands again at the dorsal portion of the thirty-third and thirty-fourth. This atrophic portion, however, is not the prunordium of the ventriculus terminalis. Unger and Brugsch compare it with the sinus terminalis found in the amphibian Embryo. It is my behef that it represents the primordium of the coccygeal medullary vestige. The extremity of the atrophic portion extends into the tip of the tail and is provided with a lumen throughout. The caudal end of the chorda appears to have adhered to the ventral wall of the spinal cord. There are 32 spinal ganglia, the thirty-second having slender nerves. The middle sacral artery and vein enter into the tail, anastomosing through branches with the anterior spinal artery.

Cite this page: Hill, M.A. (2024, April 19) Embryology Carnegie Embryo 584a. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Category:Carnegie_Embryo_584a

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