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The pylorus rests on the neck of the pancreas below and posteriorly, and is overlapped by the liver above and anteriorly. When the stomach is empty the pylorus is usually placed near (i.e. within 1 inch, 12 mm. of) the median plane, below the left lobe or sometimes the quadrate lobe of the liver, and at the level of the first lumbar vertebra, or the fibro-cartilage between this and the second lumbar. During distention it is pushed over beneath the quadrate lobe for a variable distance, but very rarely more than 1} or 2 inches to the right of the median plane. Its average position can be marked on the surface of the body by the intersection of two lines one drawn horizontally half-way between the top of the sternum and the pubic crest (Addison), the other drawn vertically a little way (inch, 12 mm.) to the right of the median plane.
During the earlier stages of gastric digestion the sphincter pylori is strongly contracted and the aperture firmly closed, but it opens intermittently to allow of the passage of properly digested portions of the food. As digestion advances the sphincter probably relaxes somewhat: but in hardened bodies a really patent pylorus is rarely or never found, which would seem to
Pyloric sphincter Circular muscle
Longitudinal muscular coat
Nucous membrane of the duodenum
DUODENUM IN A NEW-BORN CHILD. (From Stiles.)
indicate that the pylorus is normally closed, or nearly so, and that its opening is an active rather than a passive condition, as in the case of the anal canal.
As regards its size, the pylorus is stated to be about 4 inch (12.5 mm.) in diameter, but there is no doubt that this represents neither its full size nor its calibre when at rest. Foreign bodies with a diameter of 1 to 1 inch have been known to pass through the pylorus without giving rise to trouble, even in children. On the other hand, when at rest, with an empty stomach and duodenum, the aperture is practically closed.
Curvatura Ventriculi Minor.-The lesser curvature is directed towards the liver, and corresponds to the line along which a fold of peritoneum called the hepato-gastric ligament is attached to the stomach, between the pyloric and cesophageal orifices (Fig. 916). The fold connects the stomach and liver, and between its two layers the gastric vessels run along the curvature of the stomach.
While the lesser curvature is, on the whole, concave, it consists of two portions which meet and form a sharp angle, called the incisura angularis, situated nearer the pyloric than the cardiac end, though its position varies with the condition of the stomach. The superior or left portion is nearly vertical, and continues the direction of the right margin of the oesophagus, while the inferior or right portion is more nearly horizontal, when viewed from the front. The depth and acuteness of the angle between these two segments varies with the degree of distension of the stomach. When the pyloric portion of the stomach is full, the inferior portion of the lesser
imes distended, and that portion of the border becomes convex in
curvature does not form a straight line along the surface of the ī the left end it turns forwards somewhat on to the anterior surface 1, to the place where the cardiac orifice is situated. In length, the e measures some 3 to 4 inches. Ventriculi Major.—The greater curvature of the stomach is usually
· the summit of the fundus (Fig. 916), and then along the most projectthe stomach as far as the pylorus. In general, it is directed to the left but at its beginning, near the cardia, it of course looks in a different e great curvature corresponds in the greater part of its length to the
the gastro-splenic ic ligaments, folds of ssing to the spleen is verse colou
respecclose relation to it, layers, run the right
Falciform -epiploic vessels.
ligament (cut) er of the stomach, Liver
Pyloric end of er curvature, does (enlarged)
stomach uniformly curved
Subcostal line vards the pylorus
Gall. en found, called the bladder
Greater dius. The portion Transverse
colon of this sulcus is
Descending Position of
colon pyloric canal.
umbilicus 't side of this notch,
Small arvature bulges for
intestine Ascending g a chamber called pyloricum, and the unded prominence s is, in some phases narked off from the ody of the stomach Orary indentation. tations which are ind on the greater Fig. 918. – ABDOMEN OF FEMALE, SHOWING DISPLACEMENTS the body of the
RESULTING FROM TIGHT LACING. probably due to The liver is much enlarged, and extends on the left side to the
ribs, where it was folded back on itself for over an inch. eristaltic waves of
The pyloric end of the stomach and the beginning of the
duodenum are quite superficial below the liver, and all the Interior. — The an
viscera are displaced downwards. (From a photograph of a of the stomach is
body hardened by injections of formalin.) and more extensive than the posterior. It lies, when the organ is contact with the inferior surface of the left lobe of the liver medially, che diaphragm laterally, and the anterior abdominal wall below (Fig.
the stomach is empty, on the other hand, the transverse colon doubles f it, and separates its anterior surface from the liver and diaphragm I wall. osterior.—The posterior surface looks downwards and posteriorly. It ned than the anterior, and is moulded by the structures upon which
SCALE IN INCHES
SCALE IN CENTIMETRES
he left is a flattened area, passing on to the fundus, which is in con
diaphragm and the spleen. To the right of the fundus, the posterior isible into two areas, lying in different horizontal planes, a superior or, separated by a slight ridge. The superior portion, nearly vertical, t with the left kidney and supra-renal gland and the diaphragm ; rior portion, more horizontal, is in contact with the pancreas,
be incisus transverse mesocolon, and transverse colon. These structures constitute the
avature a posterior wall of the bursa omentalis of the peritoneal cavity.
man, but Between the two areas, the wall comes into contact with the splenic artery As the stor as it runs along the superior border of the pancreas.
fuodis to t The different portions into which the stomach may be divided are as follows: Pars P
angularis = Fossa for caudate lobe
greater cur Right inferior phrenic vessels Esophagus
It diffe Inferior vena cava
Left gastric artery
Left supra-renal gland
antrum pylc Portal vein
inch in Right supra-renal gland
Anterior surface of pancreas fue to the
Gastric surface of spleen
Ureter Inferior mesen
teric artery Internal spermatic vein
Ureter Right common iliac
vein Right common iliac
artery Left common iliac
Fig. 919.—THE VISCERA AND VESSELS ON THE POSTERIOR ABDOMINAL WALL.
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
When the sto atspored, know e portion of 1 mais distend tomach, when
Tee chamber 2 moet is form
angularis on the lesser curvature, and to the notch on the greater sady described. It forms a rounded chamber, capable of great distenn the stomach is empty it contracts to a narrow tube-like structure. ach is seldom completely empty, the body usually tapers from the
proximal end of the pyloric portion (Fig. 925). orica.—The pyloric portion of the stomach extends from the incisura the lesser curvature, and a variable and inconstant notch on the ture, as far as to the pyloric orifice (Fig. 925). from the body of the stomach in being more tubular in shape, and icker walls. en divided anatomically into two portions, the pyloric canal and the cum respectively. ic canal is a short more or less tubular portion rather more than ngth, extending from the sulcus intermedius on the greater curvazloric constriction. The proximal portion, called the pyloric antrum,
Diaphragm crus of diaphragm
vertebra INSVERSE SECTION OF THE TRUNK AT THE LEVEL OF THE FIRST LUMBAR VERTEBRE. ing relations of stomach, pancreas, kidneys, etc. From a subject ten years old.
ded. It is not clearly demarcated from the body of the stomach nt line of division on the greater curvature. On the lesser curvature m the incisura angularis to the pyloric canal, and it is occasionally ards on the side of the greater curvature so as to form a chamber or amera princeps" of His.
mach has been removed, after the body has been hardened, a chamber or recess on as the stomach chamber. It is (Figs. 920 and 921) a space in the upper and he abdominal cavity which is completely occupied by the stomach when that ed, but into which the transverse colon also passes, doubling up in front of the he latter is empty:
presents an arched roof, an irregularly sloping floor, and an anterior wall. ed 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 Size and the left kidney (with the supra-renal gland) and the gastric surface of the spleen; anterior to
* within 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
Str alte the transverse colon (Fig. 921), which completes the floor anteriorly.
tuless bu Finally, the anterior wall of the stomach chamber is formed by the abdominal wall, between is curteet the ribs on the left and the liver on the right side.
The leng 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, at its cap 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.
Peritoneal Relations. — The stomach is almost completely covered by
Lobus hepatis dexter
Cut surface of liver
Lobus caudatus A. gastrica sinistra
A. oceliaca Lig. hepato-duodenale A. hepatica propria
Vena porta Ductus choledochus
Fundus vesicae fellese
A. gastrica dextra
Facies anterior pancreatis
From the specimen figured in Fig. 912, after removal of the stomach.
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 oesophagus.
fenents e that the salitre
Is distance ito 125 cm
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A small irregularly triangular area (Fig. 919), about 2 inches wide and lì 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 suprarenal 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 lett 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
In the ch Poty is abo To adult, and
Displaced De part of shape, so th
a placed nea clasa very cor