The human embryonic period (first 8 weeks) is divided into 23 Carnegie stages. (More? About Carnegie) Stages are based on the external and/or internal morphological development of the embryo and are not directly dependent on either age or size. Criteria beyond morphological features include age in days, number of somites present, and embryonic length.
Special thanks to Prof Kathy Sulik for providing these scanning electron micrographs of the Carnegie stages of the early human embryo.
Clicking on the small image (or text below image) will open a page with a larger image and more information about that specific stage, images are not to scale. Note that Serial Images of embryo cross-sections are from Carnegie Stage 13 to Stage 14 (early) and Stage 20 (late). (More? Other pages using these images)
See also Developmental Notes 1
There are currently no scanning electron micrograph images currently available for these stages. The links below are to the normal bright field microscope views of these stages.
This is the last Carnegie stage of embryonic development.
Development from this point on is generally considered Fetal Development and involves general growth, system development and onging neurological development.
See also System Notes.
Note this current page is still under development and not yet complete. In addition to the Carnegie series of pages other pages on the UNSW Embryology site use images derived from Prof K. Sulik's original SEM images.