Histogenesis of the spleen in the human embryo in O'Rahilly's stages 17 to 23.

Abstract

A histological study of the spleen in 30 human embryos in O'Rahilly's stages 17-23 revealed that the splenic anlage is composed of mesenchymal elements. Furthermore, the spleen is formed by a cytoreticulum containing a number of cells similar in appearance to lymphoid elements. No evidence of a celomocapsular separation is seen in this period.