The abdominal cavity extends from the inferior
surface of the diaphragm to the level of the superior margins of the pelvis.
This cavity contains the liver, stomach, spleen, small intestine, and most of
the large intestine. The organs are
partially or completely enclosed by the peritoneal cavity, much as the heart
and lungs are enclosed by the pericardial and pleural cavities, respectively. A
few organs, such as the kidneys and pancreas, lie between the peritoneal lining
and the muscular wall of the abdominal cavity. Those organs are said to be retroperitoneal
(retro, behind). per-i-to_ -NE_ -um per-i-to_ -NE_ -al
The pelvic cavity is the portion of the ventral
body cavity inferior to the abdominal cavity. The bones of the pelvis form the walls
of the pelvic cavity, and a layer of muscle forms its floor. The pelvic cavity
contains the urinary bladder, various reproductive organs, and the distal
portion of the large intestine. The pelvic cavity of females, for example,
contains the ovaries, uterine tubes, and uterus; in males, it contains the
prostate gland and seminal glands. The pelvic cavity also contains the inferior
portion of the peritoneal cavity. The peritoneum covers the ovaries and the
uterus in females, as well as the superior portion of the urinary bladder in
both sexes. Visceral structures such as the urinary bladder and the distal
portions of the ureters and large intestine, which extend inferior to the
peritoneal cavity, are said to be infraperitoneal.