Anatomy of a Human Foetal Skull can be studied easily with this realistic foetal skull replica. The foetal skull model is a natural cast of a foetal head in the 30th week of pregnancy showing the characteristics of prenatal development. Study the anatomy of a human foetal skull with this realistic replica. The fontanelle, which becomes bone over time, are clearly visible on the foetal skull. Sutures will form along the bony plates helping fuse the foetal skull as the child ages.