Visualization of Intracranial Structures in Early Human Embryos using 3-D Computer Graphics Technique

In classic human embryology, one of the most important techniques to observe embryonic structures three-dimensionally (3-D) was to reconstruct embryos or their parts using wax plate models from serial histological sections. However, wax plate reconstruction does not allow observation of internal structures and lumens unless the models are cut after reconstruction. The development of computer graphics has enabled us to reconstruct various biologic structures on the viewing screen and to manipulate the computer images as freely as we desire. Nevertheless, until now computer reconstruction has not been used frequently to study human organogenesis. We reviewed and photographed serial histological sections of early human embryos, projected these photographed slides onto a screen and traced the outlines of specific structures under study on a digitizing pad that was interfaced with a 16 bit computer. The digitized images were combined using a software for 3-D reconstruction. With this technique, we were able to visualize the anatomical localization and interrelation of various structures inside the human head during the embryonic period. The 3-D reconstruction technique should be of potential use for the study of normal and abnormal morphogenesis.