Carnegie stages
From Wikipedia, the free encyclopedia
In embryology, Carnegie stages are a standardized system of 23 stages used to provide a unified developmental chronology of the embryo.
The stages are delineated through the development of structures, not by size or the number of days of development, and so the chronology can vary from embryo to embryo.
It only covers the first 60 days of development; at that point the term embryo is usually replaced with the term fetus.
It was based on work by Streeter (1942) and O'Rahilly and Müller (1987). The name "Carnegie stages" comes from the Carnegie Institute.
[edit] Stages
Days are approximate, and reflect the days since the last ovulation before pregnancy ("Postovulatory age").
[edit] Stage 1: 1 days
[edit] Stage 2: 3 days
[edit] Stage 3: 4 days
[edit] Stage 4: 5-6 days
- syncytiotrophoblast
- cytotrophoblast
- amniotic ectoderm
[edit] Stage 5 (a-c): 7-12 days
[edit] Stage 6: 13-15 days
[edit] Stage 7: 15-17 days
- gastrulation
- neural plate
- start of hematopoiesis
[edit] Stage 8: 17-19 days
[edit] Stage 9: 19-21 days
[edit] Stage 10: 21-23 days
[edit] Stage 11: 23-26 days
[edit] Stage 12: 26-30 days
- upper limb buds
[edit] Stage 13: 28-32 days
[edit] Stage 14: 31-35 days
[edit] Stage 15: 35-38 days
[edit] Stage 16: 36-42 days
[edit] Stage 17: 42-44 days
[edit] Stage 18: 44-48 days
[edit] Stage 19: 48-51 days
[edit] Stage 20: 51-53 days
[edit] Stage 21: 53-54 days
[edit] Stage 22: 54-58 days
[edit] Stage 23: 56-60 days
[edit] See also
[edit] External links
- Swiss embryology (from UL, UB, and UF) iperiodembry/carnegie02
- Embryology at UNSW wwwhuman/Stages/carnegie
- Photos at unsw.edu.au
- Overview at umich.edu
- Details on stages at lsuhsc.edu
- List of structures by week, at mrc.ac.uk
