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transverse mesocolon, and transverse colon.
These structures constitute the
posterior wall of the bursa omentalis of the peritoneal cavity.
Between the two areas, the wall comes into contact with the splenic artery
as it runs along the superior border of the pancreas.
The different portions into which the stomach may be divided are as follows:- P
FIG. 919.-THE VISCERA AND VESSELS ON THE POSTERIOR ABDOMINAL WALL. The stomach, liver, and most of the intestines have been removed. The peritoneum has been preserved on the right kidney, and also the fossa for the caudate lobe. When the liver was taken out, the vena cava was left behind. The stomach bed is well shown. (From a body hardened by chromic acid injections.) Fundus Ventriculi.-The fundus is that portion of the stomach which lies above a horizontal plane drawn through the oesophageal opening. It is rounded or domeshaped. This shape seldom alters, whatever the condition of the stomach may be. It is usually filled with gas.
Corpus Ventriculi.-The body of the stomach extends from the fundus to
the incisura angularis on the lesser curvature, and to the notch on the greater curvature already described. It forms a rounded chamber, capable of great distension, but when the stomach is empty it contracts to a narrow tube-like structure. As the stomach is seldom completely empty, the body usually tapers from the fundus to the proximal end of the pyloric portion (Fig. 925).
Pars Pylorica.-The pyloric portion of the stomach extends from the incisura angularis in the lesser curvature, and a variable and inconstant notch on the greater curvature, as far as to the pyloric orifice (Fig. 925).
It differs from the body of the stomach in being more tubular in shape, and possessing thicker walls.
It has been divided anatomically into two portions, the pyloric canal and the antrum pyloricum respectively.
The pyloric canal is a short more or less tubular portion rather more than an inch in length, extending from the sulcus intermedius on the greater curvature to the pyloric constriction. The proximal portion, called the pyloric antrum,
FIG. 920.-TRANSVERSE SECTION OF THE TRUNK AT THE LEVEL OF THE FIRST LUMBAR VERTEBRÆ. Showing relations of stomach, pancreas, kidneys, etc. From a subject ten years old.
is more expanded. It is not clearly demarcated from the body of the stomach by any constant line of division on the greater curvature. On the lesser curvature it extends from the incisura angularis to the pyloric canal, and it is occasionally pouched outwards on the side of the greater curvature so as to form a chamber or pouch, the "camera princeps" of His.
When the stomach has been removed, after the body has been hardened, a chamber or recess is exposed, known as the stomach chamber. It is (Figs. 920 and 921) a space in the upper and left portion of the abdominal cavity which is completely occupied by the stomach when that organ is distended, but into which the transverse colon also passes, doubling up in front of the stomach, when the latter is empty.
The chamber presents an arched roof, an irregularly sloping floor, and an anterior wall. The roof is formed partly by the visceral surface of the left lobe of the liver, and in the rest of
its extent by the left cupola of the diaphragm, which arches gradually downwards behind and on the left to meet the floor.
The floor or "stomach bed" (Fig. 921) is a sloping shelf on which the posterior surface of the stomach rests, and by which it is supported. The bed is formed posteriorly by the superior pole of the left kidney (with the supra-renal gland) and the gastric surface of the spleen; anterior to this, by the wide anterior surface of the pancreas; and more anteriorly still, by the transverse mesocolon running forwards above the small intestine, from the anterior edge of the pancreas to the transverse colon (Fig. 921), which completes the floor anteriorly.
Finally, the anterior wall of the stomach chamber is formed by the abdominal wall, between the ribs on the left and the liver on the right side.
This chamber is completely filled by the stomach, when that organ is distended. When, on the other hand, the stomach is empty and contracted, it still rests on the floor, or stomach bed, but occupies only the inferior portion of the chamber, whilst the rest of the space is filled by the transverse colon, which turns gradually upwards as the stomach retracts, and finally comes to lie both above and in front of that organ and immediately beneath the diaphragm-a fact to be remembered in clinical examinations of this region.
FIG. 921. STOMACH CHAMBER VIEWED FROM THE FRONT AND FROM BELOW.
peritoneum—the anterior surface being clothed by that of the general peritoneal sac, and the posterior surface by the anterior layer of the bursa omentalis (see p. 1162) From the lesser curvature the hepato-gastric ligament extends to the liver, whilst to the greater curvature the gastro-lienal and gastro-colic ligaments are attached Finally, a small peritoneal fold, known as the gastro-phrenic ligament, is found running from the stomach up to the diaphragm along the left side of the œsophagus.
A small irregularly triangular area (Fig. 919), about 2 inches wide and 1 inches from above downwards, during moderate distension of the stomach, on the posterior surface below and to the left of the cardia, is not covered with peritoneum, and over it the organ is in direct contact with the diaphragm, occasionally also with the superior extremity of the left kidney and the supr renal gland. From the left angle of this "uncovered area" the attachment of the gastro-lienal ligament starts; and at the right angle is the commencement of a fold through which the left gastric artery passes to the stomach. This fold is called the left gastro-pancreatic fold.
The right gastro-pancreatic fold is a fold of peritoneum passing from the right extremity of
the superior part of the pancreas to the first part of the duodenum. It encloses the hepatic artery.
Size and Capacity of the Stomach.-Probably no organ in the body varies more in size within the limits of health than the stomach. Moreover, as its tissues change so rapidly after death, measurements made on softened and relaxed organs are not only worthless but quite misleading. Consequently it is difficult, perhaps impossible, to arrive at a correct estimate of its size and capacity.
The length of the stomach in the fully distended condition is about 10 to 11 inches (25 to 27.5 cm.), and its greatest diameter not more than 4 to 4 inches (10 to 11.2 cm.); whilst its capacity in the average state rarely exceeds 40 ounces, or 1 quart.
FIG. 922. THE COURSE OF THE LARGE INTESTINE. The jejunum and ileum have been removed.
The length has been estimated by different authorities at from 10 to 13 inches (26 to 34 cm.); its diameter, from 3 to 6 inches (8 to 15 cm.); and its capacity from 1 to 5 pints. The measurements of the capacity given by Dr. Sidney Martin are probably the most accurate: he states that the capacity varies between 9 and 59 oz., with an average of from 35 to 40, or a little over a litre.
The distance in a direct line from the cardiac to the pyloric orifice varies from 3 to 5 inches (7:5 to 12.5 cm.), and that from the cardia to the summit of the fundus from 2 to 4 inches (6.2 to 100 cm.).
As regards the weight, the average of twelve wet specimens freed from their omenta was found to be 4 oz. (135 grms.), with a maximum of 7 oz. (198-45 grms) and a minimum of 3 cz. (99-22 grms.). Glendinning gives the weight as 4 oz.
In the child at birth the stomach is scarcely as large as a small hen's egg, and its capacity is about 1 oz. (28-3 grms.). In shape it corresponds pretty closely to that of the adult, and the fundus is well developed. It is vertical in position.
Displaced Stomach (Fig. 918). As a result of disease, or of constriction of the superior part of the abdomen, the stomach is occasionally displaced in position and distorted in shape, so that instead of running obliquely forwards, downwards, and to the right, it is placed nearly vertically along the left side of the vertebral column, in which direction it has a very considerable length. Its inferior part bends rather suddenly, and runs upwards
and to the right to join the pylorus, which is often placed quite superficially below the liver. As a result of the displacement, the left extremity of the pancreas is pushed downwards from the horizontal until it almost assumes a vertical position. The narrowing and inversion of the inferior margin of the thoracic framework at the same time constricts the stomach about its middle, and may lead to a bilocular condition.
Hour-glass or Bilocular Stomach.-This is a condition of the organ, by no means rare, in which the stomach is more or less completely separated into two divisions-a cardiac and a pyloric the normal arrangement in certain rodents and other animals. As a rule the former division is the larger, but occasionally the two are nearly equal, or the pyloric portion may exceed the cardiac in size. Sometimes the condition is temporary, and the result of a vigorous contraction of the circular muscular fibres at the seat of constriction. In other cases it is
permanent, and may be due to cicatricial contraction after gastric ulcer, or to some other pathological condition. The condition is more frequent in the female than the male, and is rarely
found in the foetus or child.
Position of the Stomach. When empty, or nearly so, the stomach lies in the left hypochondrium and left part of the epigastrium, with its fundus directed posteriorly towards the diaphragm, its long axis lying almost in a horizontal plane and its pyloric part running to the right to join the duodenum. In this state the whole organ is narrow and attenuated, particularly the pyloric part, which is contracted, and resembles a piece of thick-walled small intestine.
When distended, both the cardiac and pyloric parts become full and rounded (Fig. 923). It still lies within the hypochondriac and epigastric regions; but in exceptional cases, or in extreme distension, it may pass down below the subcostal plane and reach into the umbilical and left lumbar regions. As a result of the