Carnegie stage table
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 covering the first 8 weeks post-ovulation.
- 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
Carnegie Stage Table
Weeks shown in the table below are embryonic post ovulation age, for clinical Gestational Age (GA) measured from last menstrual period, add 2 weeks.
(not to scale) |
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fertilized oocyte, zygote, pronuclei | ||||
morula cell division with reduction in cytoplasmic volume, blastocyst formation of inner and outer cell mass | ||||
loss of zona pellucida, free blastocyst | ||||
attaching blastocyst | ||||
(week 2) |
implantation | |||
extraembryonic mesoderm, primitive streak, gastrulation | ||||
gastrulation, notochordal process | ||||
primitive pit, notochordal canal | ||||
Somitogenesis Somite Number 1 - 3 neural folds, cardiac primordium, head fold | ||||
Somite Number 4 - 12 neural fold fuses | ||||
Somite Number 13 - 20 rostral neuropore closes | ||||
Somite Number 21 - 29 caudal neuropore closes | ||||
Somite Number 30 leg buds, lens placode, pharyngeal arches | ||||
lens pit, optic cup | ||||
lens vesicle, nasal pit, hand plate | ||||
nasal pits moved ventrally, auricular hillocks, foot plate | ||||
finger rays | ||||
ossification commences | ||||
straightening of trunk | ||||
upper limbs longer and bent at elbow | ||||
hands and feet turned inward | ||||
eyelids, external ears | ||||
rounded head, body and limbs | ||||
The embryos shown in the table are from the Kyoto and Carnegie collection and other sources.
Historic Stages
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, June 19) Embryology Carnegie stage table. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Carnegie_stage_table
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G