UNSW Embryology

Carnegie Stage 18

© Dr Mark Hill (2008)

Acknowledgements

Carnegie Stage 18 labelled

Carnegie Stage 18

Features:

Carnegie Stage 18

Carnegie Stage 18

About Carnegie stage 18

Facts: Week 7, 44 - 48 days, 13 - 17 mm

View: Lateral view. Amniotic membrane removed.

Features:

Identify: pigmented eye, eyelid, nasolacrimal groove, external acoustic meatus, heart, digital rays, liver prominance, thigh, ankle, foot plate, umbilical cord

Events

Ectoderm: sensory placodes, lens pit, otocyst,nasal pits moved ventrally, fourth ventricle of brain

Mesoderm: heart prominence

Head: 1st, 2nd and 3rd pharyngeal arch, forebrain, eye, auricular hillocks

Body: heart, liver, umbilical cord

Limb: upper and lower limb buds, foot plate, wrist, hand plate with digital rays

Additional Information

Sensory: Vomeronasal organ (VNO) first stage this structure is visible. Sherwood RJ, McLachlan JC, Aiton JF, Scarborough J. The vomeronasal organ in the human embryo, studied by means of three-dimensional computer reconstruction. J Anat. 1999 Oct;195 ( Pt 3):413-8.

Limbs: Muscle development - thick and thin filaments with faint Z-lines appeared in the peripheral cytoplasm of the myotube. Rough endoplasmic reticulum (RER), free ribosomes, and mitochondria increased in number. Tanaka O, Shinohara H, Oguni M, Yoshioka T. Ultrastructure of developing muscle in the upper limbs of the human embryo and fetus. Anat Rec. 1995 Mar;241(3):417-24

Carnegie Stages 19

Stage 19 Unlabelled | Stage 19 Labelled

Glossary of Terms

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Carnegie Stage images

The Kyoto Collection images are reproduced with the permission of Prof. Kohei Shiota for tutorial/revision purposes and cannot be reproduced electronically or in writing without permission.

UNSW Embryology ISBN: 978 0 7334 2609 4

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