The =stomach= is relatively large. Its capacity in a dog weighing about
40 pounds is about six to seven pints.
Colin estimates the average capacity at about 3 liters (ca. 6½ pints),
with a range between 0.6 and 8 liters (ca. 1⅓ to 17½ pints). Neumayer
gives the capacity as 100 to 250 c.c. per kilogram of body-weight (ca.
2.7 ounces per pound). The average capacity of the human stomach is
estimated at 35 to 40 ounces—only about one-half of that of a dog of
medium size.
When full it is irregularly pyriform. The left or cardiac part (Corpus
ventriculi) is large and rounded, while the right or pyloric part (Pars
pylorica) is small and cylindrical. When empty, or nearly so, the left
sac is strongly contracted; the pyloric part is not materially affected
by variations in the amount of ingesta.
The parietal surface of the full stomach is very extensive, strongly
convex, and faces partly forward, but largely to the left. It is related
to the liver, the left part of the diaphragm, and the left and ventral
abdominal wall as far back as a transverse section through the second or
third lumbar vertebra.
The visceral surface is much less extensive and is considerably
flattened; it faces chiefly to the right, and is related to the
intestine, pancreas, and left kidney.
The upper part of the lesser curvature is nearly straight and vertical,
but the lower part forms a deep, narrow angle, due to the fact that the
pyloric part is directed sharply forward and upward.
The greater curvature is nearly four times as long as the lesser
curvature. In the full stomach it extends considerably behind the left
costal arch (having carried the spleen backward); ventrally, it lies on
the abdominal wall, almost midway from the xiphoid cartilage to the
pubis.
[Illustration: