The uterine cavity is the inside of the uterus. The uterine cavity is the inside of the uterus. It is triangular in shape, the base (broadest part) being formed by the internal surface of the fundus between the orifices of the uterine tubes, the apex by the internal orifice of the uterus through which the cavity of the body communicates with the canal of the cervix. The uterine cavity of the body of the uterus is a mere slit, flattened antero-posteriorly. This article incorporates text in the public domain from page 1260 of the 20th edition of Gray's Anatomy (1918)