Placed behind the chest, from which it is separated by the diaphragm, the abdominal cavity passes backward and becomes continuous with the pelvis. It is the largest cavity of the body, bounded above by the loins or lumbar division of the spine, below and at the sides by muscles, tendons, and elastic tissue, already described. Contained within it are the stomach and bowels, the liver, pancreas, spleen, kidneys, and numerous vessels, nerves, and lymphatic glands. In the female it also contains the ovaries and the horns of the uterus.
For convenience of description of the position of parts within it the abdomen is arbitrarily divided into nine portions, of which three are situated in front, three in the middle, and three behind. This division is effected by cutting the body across by two imaginary vertical planes, one passing through the lower extremity of the fifteenth rib, the other transversely through the external angle of the haunch-bone. The three divisions thus made are subdivided by two longitudinal planes which fall through the centre of Poupart's ligament on the right and left side respectively, and cut each of the three primary divisions into a central and two lateral portions. As a result of this we get the nine parts described and figured below.