Introduction
Facts
Week 8, 51 - 53 days, 18 - 22 mm
Events
Events
Ectoderm: sensory placodes, lens pit, otocyst, nasal pits moved ventrally, fourth ventricle of brain
Mesoderm: heart prominence, ossification continues
Head: forebrain, eye, external acoustic meatus
Features
scalp vascular plexus, eylid, eye, nose, external acoustic meatus, auricle of external ear, arm, elbow, wrist, liver prominence, digital rays
Identify: straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, scalp vascular plexus, digital rays, liver prominance, thigh, ankle, foot plate, umbilical cord
- Links: Week 8 | System Development | Lecture - Limb | Lecture - Head Development | Lecture - Sensory | Science Practical - Head | Science Practical - Sensory | Science Practical - Urogenital | Historic - Skull Development | Category:Carnegie Stage 20 | Stage 21
- 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
Kyoto Collection
View: This is a dorsolateral view of embryo. Amniotic membrane removed.
Image source: Embryology page Created: 19.03.1999
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 stage 20: 8517 Right | 8517 Anterior | 8517 Left | 7906 Right | 7906 Anterior | 7906 Left | 7274 Right | 7274 Anterior | 7274 Left
iBook - Carnegie Embryos
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- 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).
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Additional Images
Stage 20 Optical Projection Tomography
Historic Images
Skull - Dorsal aspect of base with the basioccipital in horizontal plane.
Skull - Right half base of cartilaginous skull.
Skull - Dorsal aspect of cartilaginous and membranous skull.
Skull - Median sagittal aspect.
Skull - Ventral aspect of base.
Skull - Lateral aspect and cervical vertebrae with brain and cervical cord and hypophysis.
Skull - Lateral aspect and cervical vertebra with brain, cervical cord, and nerves.
Skull - Lateral view and cervical vertebrae with overlying membranous skull and dorsal membrane.
Skull - Dorsal aspect of sphenoid cartilage.
Skull - Dorsal aspect of sphenoid cartilage.
Skull - Lateral view of right otic region.
Skull - Lateral view of right otic region showing relations of facial nerve.
Skull - Lateral view of base with deeper muscles of occipital region, mouth and pharynx.
Skull - Lateral view of part of cartilaginous and membranous skull.
Skull - Dorsal view of temporal and occipital cartilages.
Left lateral view of larger blood-vessels of the brain.
Human embryonic shoulder girdle
- 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
Cite this page: Hill, M.A. (2024, June 27) Embryology Carnegie stage 20. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Carnegie_stage_20
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- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G