The headline on a Jan. 24 Science Page graphic incorrectly said the Multi-Dimensional Human Embryo project involved images taken of fetuses in utero. In fact, the images were all obtained from museum embryo specimens. The graphic also noted that a University of Michigan researcher and colleagues created the images but failed to note that they were working at Duke University. (Published 02/02/2000)

The Multi-Dimensional Human Embryo project is a collaboration funded by the National Institute of Child Health and Human Development to produce and make available on the Internet ( three-dimensional images of the human embryo. The images are intended for students, researchers, clinicians and the general public interested in studying and teaching human development.

Step by Step

The project uses "Carnegie Stages," a system used by embryologists to describe the maturity of embryos based on external features as opposed to chronological age or size.

Bradley R. Smith of the University of Michigan and colleagues use a technique called magnetic resonance microscopy to create three, three-dimensional images of each embryo.

CAPTION: These "volume-rendered" images of a "stage 19" embryo were created by combining all the "slice" images together to form three-dimensional images of the entire embryo with complete anatomical detail. A "stage 19" embryo typically would be about 47 days after ovulation.

CAPTION: Each MRI image is broken down into a series of "slice" images from three separate perspectives -- coronal, axial and sagittal. The image above is an example of the "coronal" sections of a "stage 19" embryo, showing detailed anatomical structures.