Examination of three-dimensional movements in human embryos using computer imaging technology.

This paper describes the use of computer imaging technology to study in three dimensions the dynamics of differentiations in human embryos. Three-dimensional computer reconstruction technology was used to build a series of models of the brain/face and the ear region from fixed, serially sectioned embryos at representative stages. When certain principles are followed each model can be equated to one frame on a motion picture film. The dynamics of differentiation are then revealed as changes in size, shape and position (growth movements) of multiple structures as they build the definitive arrangement.