the space bounded by the abdominal walls, the diaphragm, and the pelvis; it usually is arbitrarily separated from the pelvic cavity by a plane across the superior aperture of the pelvis; however, it may include the pelvis with the abdomen (see abdominopelvic cavity); within the cavitas lie the greater part of the organs of digestion, the spleen, the kidneys, and the suprarenal glands. Syn: cavitas abdominalis [NA], cavum abdominis, enterocele(2).