Examination of the uterine cervix by ultrasound in normal and pathologic pregnancy.

New possibilities of examination of the uterine cervix are provided by sonography in normal and pathologic pregnancy. Basic data of the ultrasonographic anatomy of the non pregnant uterine cervix is presented first: the length of the cervix as well as the diameters at the levels of external and internal os. These data are compared then with those in normal, physiologic pregnancy, and contrasted with those obtained in cases of incompetent cervix. In this group shortening of the cervical length, opening of the internal os and the funnel, or hour-glass-like herniation of the fetal membranes were characteristic findings. The method seems to be suitable for the assessment of the effectivity of cerclage operations for cervical incompetence.