Carnegie stage 21: Difference between revisions
(New page: Image source: [http://embryology.med.unsw.edu.au/wwwhuman/Stages/stage21.htm Embryology page Created: 19.03.1999] ===Carnegie Stages Link=== 1 | [[Carnegie_stage_3|...) |
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'''Facts:''' Week 8, 53 - 54 days, 22 - 24 mm | |||
'''View:''' Lateral view. Amniotic membrane removed. | |||
'''Features:''' scalp vascular plexus, eylid, eye, nose, auricle of external ear, arm, elbow, wrist, knee, notch between digital rays, umbilical cord | |||
'''Identify:''' straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, scalp vascular plexus, webbed digits, liver prominance, thigh, ankle, foot plate, umbilical cord | |||
Events | |||
Ectoderm: sensory placodes, nasal pits moved ventrally, fourth ventricle of brain | |||
Mesoderm: heart prominence, ossification continues | |||
Head: nose, eye, external acoustic meatus | |||
Body:straightening of trunk, heart, liver, umbilical cord | |||
Limb: upper limbs longer and bent at elbow, foot plate with digital rays begin to separate, wrist, hand plate with webbed digits | |||
Image source: [http://embryology.med.unsw.edu.au/wwwhuman/Stages/stage21.htm Embryology page Created: 19.03.1999] | Image source: [http://embryology.med.unsw.edu.au/wwwhuman/Stages/stage21.htm Embryology page Created: 19.03.1999] | ||
Revision as of 13:14, 4 August 2009
Facts: Week 8, 53 - 54 days, 22 - 24 mm
View: Lateral view. Amniotic membrane removed.
Features: scalp vascular plexus, eylid, eye, nose, auricle of external ear, arm, elbow, wrist, knee, notch between digital rays, umbilical cord
Identify: straightening of trunk, pigmented eye, eyelid, nose, external acoustic meatus, scalp vascular plexus, webbed digits, liver prominance, thigh, ankle, foot plate, umbilical cord
Events
Ectoderm: sensory placodes, nasal pits moved ventrally, fourth ventricle of brain
Mesoderm: heart prominence, ossification continues
Head: nose, eye, external acoustic meatus
Body:straightening of trunk, heart, liver, umbilical cord
Limb: upper limbs longer and bent at elbow, foot plate with digital rays begin to separate, wrist, hand plate with webbed digits
Image source: Embryology page Created: 19.03.1999
Carnegie Stages Link
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About Carnegie Stages
Carnegie stages are named after the famous US Institute which began collecting and classifying embryos in the early 1900's. Stages are based on the external and/or internal morphological development of the embryo, and are not directly dependent on either age or size. The human embryonic period proper is divided into 23 Carnegie stages. Carnegie stages are based on the external and/or internal morphological development of the embryo, and are not directly dependent on either age or size. Criteria beyond morphological features include age in days, number of somites present, and embryonic length.
The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota. Scanning electron micrographs of the Carnegie stages of the early human embryos are reproduced with the permission of Prof Kathy Sulik. Images are for educational tutorial/revision purposes and cannot be reproduced electronically or in writing without permission.
UNSW Embryology Links
Glossary Links
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- Dr Mark Hill 2009, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
