Carnegie stage 12: Difference between revisions

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Embryology - 19 Apr 2024 Expand to Translate
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Introduction

Facts

Week 4, 26 - 30 days, 3 - 5 mm, Somite Number 21 - 29

Gestational Age GA week 6

Summary

Ectoderm: Neural tube continues to close, Caudal neuropore closes, forebrain
Mesoderm: continued segmentation of paraxial mesoderm (21 - 29 somite pairs), heart prominence
Head: 1st, 2nd and 3rd pharyngeal arch, forebrain, site of lens placode, site of otic placode, stomodeum
Body: heart, liver, umbilical, early upper limb bulge

Features

Features: day 26, 27 somites, forebrain, site of lens placode, site of otic placode , stomodeum, 1st pharyngeal arch, 2nd pharyngeal arch, 3rdpharyngeal arch, heart prominence, somite
Identify: forebrain, site of lens placode, site of otic placode, stomodeum, first pharyngeal arch, second pharyngeal arch, third pharyngeal arch, heart prominence, somite

Week:	1	2	3	4	5	6	7	8
Carnegie stage:	1 2 3 4	5 6	7 8 9	10 11 12 13	14 15	16 17	18 19	20 21 22 23

Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline

Bright Field

Scanning EM

Image Source: Scanning electron micrographs of the Carnegie stages of the early human embryos are reproduced with the permission of Prof Kathy Sulik, from embryos collected by Dr. Vekemans and Tania Attié-Bitach. Images are for educational purposes only and cannot be reproduced electronically or in writing without permission.

Embryonic Development

Kyoto Collection

View: Lateral view, day 26, 27 somites, Amniotic membrane removed.

Image source: The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota and Prof. Shigehito Yamada, Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan for educational purposes only and cannot be reproduced electronically or in writing without permission.

Carnegie Collection

Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline

iBook - Carnegie Embryos
	iTunes link \| iBook Store Description - Imagine the excitement of seeing this incredible early period of human development for the first time. Now consider that much of our initial understanding of human development is based upon study of historic embryo collections. You can now look at these historic images of the first 8 weeks after fertilisation and explore for yourself the changes that occur in human development during this key period. This current book is designed as an atlas of the Carnegie embryo stages with some brief notes and additional information covering the first 8 weeks of development. These images are from from the beginning of last century and are one of the earliest documented series of human embryos collected for basic research and medical education on development. I hope you enjoy learning about the amazing early events that begin to make and shape us. This is the second book in a series of educational releases from UNSW Embryology. Release: First Edition - Mar 12, 2012 ISBN 978-0-7334-3148-7 Print Length 82 Pages, 25.8 MB Language English. PDF Preview version 3.87 MB (Read the associated information, this is an edited educational preview version with many features not functioning). The current website also includes numerous embryo images from this textbook (see Embryonic Development and Carnegie Embryos).

Hill Collection


right view	left view

Links: Hill Collection

Hinrichsen Collection

Hinrichsen collection Human Embryo ME50 (stage12).

Note the developing pharyngeal arches, otic and optic placodes, and heart in this left lateral view of the embryo.

Image source: The Hinrichsen Collection images are reproduced with the permission of Prof. Beate Brand-Saberi, Head, Department of Anatomy and Molecular Embryology, Ruhr-Universität Bochum. Images are for educational purposes only and cannot be reproduced electronically or in writing without permission.

Historic Embryology

Chicago Collection H1093 and H984

H1093 and H984 are University of Chicago Collection 22 and 23 somite embryos respectively, described by Wen, I. C., The anatomy of human embryos with seventeen to twenty-three pairs of somites J. Comp. Neural, 1928, 45:301-376.

Events

Somitogenesis - stages 12 and 13 embryo somite 1 has dispersed and is now contributing to the hypoglossal cord. Therefore “in embryos with more than 20 somites” (beginning of stage 12), the first ones visible “actually are second somites”.^[1]
hearing - otic vesicle (otocyst) is forming and connects by a narrow pore with the surface^[2] Otocyst ventral wall contributes to the vestibulocochlear crest.

References

↑ Arey, L. B. 1938. The history of the first somite in human embryos. Carnegie Instn. Wash. Publ. 496, Contrib. Embryoi, 27, 233-269.
↑ Streeter GL. Developmental horizons in human embryos. Description of age group XI, 13 to 20 somites, and age group XII, 21 to 29 somites. (1942) Contrib. Embryol., Carnegie Inst. Wash. Publ. 541, 30: 211-245.

Wen, I. C., The anatomy of human embryos with seventeen to twenty-three pairs of somites J. Comp. Neural, 1928, 45:301-376.

Additional Images

Stage 12 Optical Projection Tomography

Historic Images

Historic Disclaimer - information about historic embryology pages
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)

Heard model of Carnegie embryo 588
Right and left profile views of a wax-plate reconstruction of the main arteries and veins in a human embryo 4 mm.
Gray's Anatomy Fig. 472
Graphic reconstruction of embryo from serial sections PMID 17232769
22 Somites
23 Somites
23 Somites
23 Somites
23 Somites

Historic Papers: 22 Somites | 23 Somites | 25 Somites | 27 Somites | Brain Vascular System of the Human Embryo

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2024, April 19) Embryology Carnegie stage 12. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Carnegie_stage_12

What Links Here?

[1] Arey, L. B. 1938. The history of the first somite in human embryos. Carnegie Instn. Wash. Publ. 496, Contrib. Embryoi, 27, 233-269.

[2] Streeter GL. Developmental horizons in human embryos. Description of age group XI, 13 to 20 somites, and age group XII, 21 to 29 somites. (1942) Contrib. Embryol., Carnegie Inst. Wash. Publ. 541, 30: 211-245.

[1]

[2]

@@ Line 85: / Line 85: @@
 ==Hinrichsen Collection==
-[[File:ME50 001.jpg|400px]]
+[[File:ME50 001.jpg|400px]][[File:ME50 001.jpg|400px]]
 Hinrichsen collection Human Embryo ME50 ([[Carnegie stage 12|stage12]]).