Carnegie stages

From WikiMD's Wellness Encyclopedia

Carnegie Stages refer to a standardized system of 23 stages used to provide a unified developmental chronology of the embryo. The stages are based on the external and/or internal morphological development of the embryo, and not on the size or the number of days of development. The system was first introduced by George Linius Streeter and is named after the Carnegie Institution of Washington where Streeter worked.

Etymology[edit | edit source]

The term "Carnegie Stages" is derived from the Carnegie Institution of Washington, where the system was first developed. The institution itself is named after Andrew Carnegie, a Scottish-American industrialist and philanthropist.

Development of the Stages[edit | edit source]

The Carnegie Stages were developed by George Linius Streeter, an American anatomist and embryologist. Streeter was interested in the development of the human embryo and sought to create a system that would standardize the stages of embryonic development. The stages are based on the morphological characteristics of the embryo, rather than the number of days since fertilization, which can vary. This makes the Carnegie Stages a more accurate and reliable system for embryonic development.

Stages[edit | edit source]

The Carnegie Stages consist of 23 stages, each representing a specific phase in the development of the human embryo. The stages are as follows:

  • Stage 1: Fertilization
  • Stage 2: Beginning of the first cell division
  • Stage 3: Morula
  • Stage 4: Blastocyst
  • Stage 5: Implantation
  • Stage 6: Formation of the primitive streak
  • Stage 7: Gastrulation
  • Stage 8: Neurolation
  • Stage 9: Formation of the somites
  • Stage 10: Formation of the neural tube
  • Stage 11: Formation of the foregut and hindgut
  • Stage 12: Formation of the heart tube
  • Stage 13: Formation of the pharyngeal arches
  • Stage 14: Formation of the limb buds
  • Stage 15: Formation of the liver bud
  • Stage 16: Formation of the kidney bud
  • Stage 17: Formation of the eye and ear buds
  • Stage 18: Formation of the nasal pit
  • Stage 19: Formation of the lung buds
  • Stage 20: Formation of the genital tubercle
  • Stage 21: Formation of the digits
  • Stage 22: Formation of the external ear
  • Stage 23: Completion of organogenesis

Related Terms[edit | edit source]

See Also[edit | edit source]

Carnegie stages Resources
Wikipedia
WikiMD
Navigation: Wellness - Encyclopedia - Health topics - Disease Index‏‎ - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes

Search WikiMD

Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD

WikiMD's Wellness Encyclopedia

Let Food Be Thy Medicine
Medicine Thy Food - Hippocrates

WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.

Contributors: Prab R. Tumpati, MD