UNSW Embryology

Carnegie Stage 16

© Dr Mark Hill (2008)

Acknowledgements

Carnegie Stage 16

Carnegie Stage 16 (day 40)

Features: eye showing retinal pigment, nasolacrimal groove, nasal pit, fourth ventricle of brain, umbilical cord, 1st and 2nd pharyngeal arches, cervical sinus, heart, developing arm with hand plate, foot plate

Additional Stage 16 Information

Below are events occurring at this stage in development. Text information is followed by a link to the original reference source.

Limbs: upper limb nerves: median nerve, radial nerve and ulnar nerve entered into hand plate. Shinohara H, Naora H, Hashimoto R, Hatta T, Tanaka O. Development of the innervation pattern in the upper limb of staged human embryos. Acta Anat (Basel). 1990;138(3):265-9.

upper limb bud myoblasts spindle shaped and oriented parallel to limb bud axis. 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.

Notochord: layer of microfibrils in the notochordal sheath initially separated from the notochord. Glycogen, mucoprotein, neutral mucopolysaccharides, and glycolipids began to increase in the mesenchymal cells around the notochord. Shinohara H, Tanaka O. Development of the notochord in human embryos: ultrastructural, histochemical, and immunohistochemical studies. Anat Rec. 1988 Feb;220(2):171-8.

Heart: outflow tract elliptical configuration with four cushions, the two larger fusing at this stage. Semilunar valve leaflets form at the downstream end of the cushions. Yu IT, Hutchins GM. Truncus arteriosus malformation: a developmental arrest at Carnegie stage 14. Teratology. 1996 Jan;53(1):31-7.

Lip and Palate: components of the upper lip, medial nasal prominence and maxillary process. The median palatine process appears. Yoon H, Chung IS, Seol EY, Park BY, Park HW. Development of the lip and palate in staged human embryos and early fetuses. Yonsei Med J. 2000 Aug;41(4):477-84.

Carnegie Stage 16

Carnegie Stages 17

Stage 17 Unlabelled | Stage 17 Labelled

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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.

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