The round ligaments (ligamentum teres uteri) are two flattened bands between 10 and 12 cm. in length, situated between the layers of the broad ligament in front of and below the uterine tubes. Commencing on either side at the lateral angle of the uterus, this ligament is directed forward, upward, and lateralward over the external iliac vessels. It then passes through the abdominal inguinal ring and along the inguinal canal to the labium majus, in which it becomes lost. The round ligaments consists principally of muscular tissue, prolonged from the uterus; also of some fibrous and areolar tissue, besides bloodvessels, lymphatics; and nerves, enclosed in a duplicature of peritoneum, which, in the fetus, is prolonged in the form of a tubular process for a short distance into the inguinal canal. This process is called the canal of Nuck. It is generally obliterated in the adult, but sometimes remains pervious even in advanced life. It is analogous to the saccus vaginalis, which precedes the descent of the testis.