The caudal end of the body is a frequent site for the development of cysts, tumors and fistulas of vestigial origin. Here numerous anlages appear almost simultaneously, some of which proceed through a complex series of changes to form the final organ or system while others develop to a certain stage only to regress and be resorbed. Disturbances in the developmental sequence, arrested development, heterotopia and failure of regression may be factors contributing to the formation of anomalous conditions. The persistence of caudal vestiges and the possibility of their subsequent development into tumors and cysts have been widely acknowledged. These lesions are regarded with much interest not only by the surgeon and the pathologist but also by the embryologist, because of the links which they provide in establishing the chain of evidence concerning the fate of certain embryonal structures.
The present communication will review the embryology of the caudal end