It refers to the mesentery of the uterus. Mesentery refers to a double layer of peritoneum which joins itself to the posterior wall of the abdominal cavity and renders support to the small intestines.
It lies next to the Mesosalpinx. It is actually the section of the broad ligament of the uterus that lies under the Mesosalpinx.
It comprises of important structures of the body, which include the ureter. It contains the greater section of the broad uterine ligament, leaving out only the sections that lie next to the ovary (Mesosalpinx) and the uterine tube.
Get a proper idea about the appearance of this organ of the female reproductive system with the aid of these useful images.
Picture 1 – Mesometrium
Picture 2 – Mesometrium Image