Three-dimensional reconstructions of the primary palate region in normal human embryos

Our knowledge of the precise spatial relationships of human primary palate morphogenesis remains poorly defined. This is due to intrinsic difficulties that exist in the study of the subject matter and a lack of adequate methodologies. We present a novel new method to allow precise three-dimensional (3-D) visualization of developing embryonic structures in previously sectioned embryos. In our study we focus on human primary palate development. Five normal human embryos from the Carnegie collection were used. 3-D reconstructions appear similar to scanning electron micrographs (SEM); however, unlike in SEM studies, the original specimen has been previously sectioned histologically. 3-D reconstruction from serial sections involved 1) histological preparation of specimen, 2) projection onto digitizing board, 3) digitization, 4) automated reassembly, and 5) relay to interactive optical disc recorder. Detailed observations of each reconstruction were then made. Data generated in this manner may also be used in the near future for quantitative morphometrics. Thus, 3-D reconstruction techniques presented in this paper generated precise spatial information on the development of the human primary palate.