The cavity, also known as the cavity of the major or greater pelvis, is bounded by, but excludes: superiorly an artificial plane that extends from the symphysis pubis to the superior iliac crests; and inferiorly the superior pelvic aperture. It is bounded on either side by the ilium; and in front it is incomplete, presenting a wide interval between the anterior borders of the ilia. It forms the inferior volume of the abdomen proper cavity, which includes a number of parts of structures of the intra-abdominal proper e.g. historically the cavity of false pelvis has been described as containing the 'iliac colon' which is a segment of the descending colon within the volume of the false pelvis. Note, the contents and structures that form the boundaries are excluded from the cavity.