The placenta is limited internally (fetal aspect) by the amniotic membrane and chorionic plate; externally (maternal aspect) by the basal plate. Basal plate consists of following structures from outside inwards; Pa of the compact and spongy layer of the decidua basalis Nitabuch's layer of fibrinoid degeneration of the outer syncytiotrophoblast at the junction of the cytotrophoblastic shell and decidua Cytotrophoblastic shell Syncytiotrophoblast Ref: Textbook of Obstetrics by D C Dutta, 6th edition, Page 30.