'The anatomy lesson of Dr. Frederik Ruysch' of 1683, a milestone in knowledge about obstetrics.

'The anatomy lesson of Dr. Frederik Ruysch' (1683) belongs to the famous collection of group portraits of the Amsterdam Guild of Surgeons. In this painting, Ruysch is portrayed with a dissected corpse of a newborn, which was still attached to its placenta. Several guild officials as well as his son, who is holding a skeleton of an infant, are surrounding him. Dissection of a child instead of an executed criminal was very uncommon at that time. We therefore investigated the medical background of the painting, with the question why Ruysch was depicted with these obstetrical subjects. To this end, the contents of Ruysch's original works and his over 300-year-old anatomical specimens in the Museum of Anthropology and Ethnography (Kunstkamera) in St. Petersburg were studied and described in the context of the painting. Major contributions to anatomical knowledge and to human development should be attributed to Ruysch, and these provided the essentials of the composition depicted in this painting.