The confusion of terms between the radiological literature and the gynaecological and anatomical literature regarding the definitions of the infantile and the hypoplastic uterus are described. The history of this confusion is traced. The two types of uterus were clearly defined by K. Menge and K.v. Oettingen in 1930. The infantile uterus shows an abnormal relationship between the length of the cervix and the length of the uterine cavity of 1:1 or 2:1, whereas the hypoplastic uterus shows a normal relationship between the length of the cervix and the length of the uterine cavity of approximately 1:2.