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abdomen and certain other cavities, is to facilitate the movements of the contained riscera during any changes in size or form which they or their containing cavity hay undergo. As a result of this arrangement, notwithstanding the tonic pressure the abdominal wall on its contents, the stomach and intestines are free to move with the greatest ease and the least degree of friction, when any change takes place her in the organs themselves or in their surroundings.

The peritoneum is a thin glistening membrane, which may aptly be compared 22 coat of varnish lied to the inner

Round ligament of liver

Falciform ligament ect of the ab

Foramen epiploicum

Lesser omentum (cut)

Portal vein inal walls, and

Stomach e surface of the ained viscera, ut where these irectly applied lightnent e walls or to inother. It throughout its extent a conand distinct ut it is united nately to the

and follows zularities of Is so closely,

ligament appears at

Right kidney t to be a

layer of ls, rather Small intestine

The mesentery separate Outside

Aorta neum lies bserosascribed che perionnected SS intie fascial e abdoS and minal

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Descending colon

B

on of which of the in as

parivhich scera neum

Fig. 915.-DIAGRAMMATIC TRANSVERSE SECTIONS OF ABDOMEN, to show the

peritoneum on transverse tracing. A, at level of foramen epiploicum ; B, lower down. In A note, one of the short gastric arteries passing to the stomach between the layers of the gastro - lienal ligament, and also the foramen epiploicum leading into the bursa omentalis which lies behind the stomach.

he peritoneum, beginning in front, we find that it lines the deep terior abdominal wall, and is continued upwards to the inferior phragm (Fig. 914), the greater portion of which it covers. From t of the diaphragin it is reflected or carried forwards on to the of the liver. From the liver it can be traced over the stomach, her abdominal viscera to the pelvis. In like manner, when traced e anterior wall, the membrane will be found to line the sides of assing backwards to clothe the posterior abdominal wall, and the viscera lying upon it (Fig. 914). It should be pointed out that all the abdominal viscera are either directly fixed by connective tissue to the posterior abdominal wall, or connected by blood vessels with it. In the former case the peritoneum is reflected directly from the wall on to the viscera; in the latter it runs along the blood vessels to reach the viscera, which it clothes, and then returns to the wall on the opposite sides of the vessels, which it thus encloses in a fold.

Whilst the greater part of the general peritoneal cavity lies anterior to the various abdominal viscera, covering them over and dipping down between them, it should be mentioned that there is a special diverticulum derived from it, situated mainly behind the stomach, and covering its posterior surface; this is known as the bursa omentalis (O.T. small sac), and it will be described in detail later. The aperture through which one sac communicates with the other is termed the foramen epiploicum (Winslowi) (0.T. foramen of Winslow).

In passing from organ to organ, or from these to the abdominal wall, the peritoneum forms numerous folds, the principal ones being as follows:

(1) Omentum Majus.—The greater omentum hangs down like an apron from the transverse colon, in front of the coils of the jejunum and ileum. It consists embryologically of four layers of peritoneum, two anterior and two posterior, which are usually, in the adult, adherent to one another. The four layers form a thin, translucent, and often perforated membrane. The anterior two layers were originally connected with the stomach above, and passed down in front of the transverse colon, but as development proceeds they become adherent to the anterior surface of the transverse colon. The fold which extends from the stomach to the colon is termed the gastro-colic ligament. If the anterior two layers are separated from the posterior two and from the front of the transverse colon, a cavity is formed, continuous with the bursa omentalis, and the anterior layers of the greater omentum are directly continuous with the layers of the gastro-colic ligament. This condition is that usually described in English text-books as the normal adult condition and is represented in Fig. 914, where the gastro-colic ligament is separated from the transverse colon, and passes in front of the transverse colon directly into the anterior layers of the omentum majus, and the great omentum thus descends from the stomach above.

(2) Omentum Minus.— The lesser omentum is a fold passing from the inferior surface of the liver to adjacent organs. It consists of two, or occasionally three, . portions :

(a) The ligamentum hepatogastricum, a wide peritoneal fold, extending from the left end of the porta hepatis, the fossa of the ductus venosus, and partly also from the concave surface of the left lobe of the liver and the caudate process, to the lesser curvature of the stomach, where it is continued into the peritoneal coats of the anterior and posterior surfaces of that organ.

(6) The ligamentum hepatoduodenale passes from the porta hepatis to the pars superior of the duodenum. On the left this fold is continuous with the hepatogastric ligament, on the right it ends in a rounded margin. Traced downwards the layers of peritoneum which form it clothe the commencement of the duodenum on two sides, and are continued into the transverse mesocolon, and into the duodeno-renal ligament.

(c) The ligamentum hepatocolicum is an occasional fold passing from the region of the gall-bladder to the transverse colon and right colic flexure.

(3) Ligamentum Gastrolienale.-The gastro-splenic ligament (O.T. gastro-splenic omentum)is a double layer of peritoneum extending between the fundus of the stomach and the hilum of the spleen, and continuous below with the gastro-colic ligament.

(4) The ligamentum gastrocolicum extends from the greater curvature of the stomach to the transverse colon. It consists of two layers of peritoneum, continuous above with the layers on the anterior and posterior surfaces of the stomach, and below with the anterior layers of the great omentum.

In English text-books this is not usually recognised as a separate ligament, but is considered to be a portion of the greater omentum, and to pass downwards in front of the transverse colon. It will be found, however, that the arrangement in the adult is usually that described above.

Mesenteries are folds of peritoneum which unite portions of the intestine o the posterior abdominal wall, and convey to them their vessels and nerves. here are several mesenteries, e.g. the mesenterium (mesentery proper), which nnects the jejunum and ileum to the posterior abdominal wall, the mesocolon insversum (transverse mesocolon), the mesocolon pelvinum (pelvic mesocolon),

occasionally others. Other folds, specially named, but described elsewhere, are the ligaments of the r, the so-called "false ligaments” of the bladder, the lieno-renal ligament, and broad ligaments of the uterus.

VENTRICULUS.

he stomach is the large dilatation found on the digestive tube immediately it enters the abdomen (Figs. 916 and 920). It constitutes a receptacle in which pod accumulates after its passage through the æsophagus, and in it take some of the earlier processes of digestion, resulting in the conversion of the nto a viscid soup-like mixture, known as chyme. The chyme as it is formed red to escape intermittently through the pylorus, into the small intestine, where estive processes are continued.

form and the position of the stomach present great variations, not only different individuals, but also in the same individual at different times. ree to which it is filled, the size and position of adjacent organs, the con'the abdominal walls, and even the assumption of the erect or the recumbent can influence its shape and relations. cent years, examination of the stomach by X-rays has afforded information,

unattainable, of the shape and position of the stomach in life, and of the vhich it undergoes. The results obtained by this method have considerified current conceptions regarding the stomach in the living. A necessary ry to the proper comprehension of these appearances is à careful study nach as it presents itself to anatomical examination. al Shape and Position.-In shape, the stomach may be described as an - piriform or conical organ, with a wide end directed upwards and

lying deeply in the hollow of the diaphragm, mainly in the left hyporegion, and a narrow tapering extremity which passes downwards and id is bent over to the right side, in the epigastric region. 5 axis of the organ forms a spiral curve, directed downwards, anteriorly right, and finally backwards. rior end, or fundus, is almost always dome-shaped, and is distended with wall is thinner and more flaccid than that of the lower portion, which d somewhat cylindrical in shape. f the stomach are composed of an inner thick layer of mucous membrane (tunica rted by submucous tissue (tela submucosa), a muscular coat, consisting of three less complete, of muscle fibres (tunica muscularis), running in different directions, lly by a serous, peritoneal investment (tunica serosa). The special chara ers of ells will be described later. ch presents the following parts for examination :es, an anterior (paries anterior) directed at the same time forwards and la posterior (paries posterior) which looks posteriorly and also to the urfaces meet above and to the right at the lesser curvature, curvatura w at the greater curvature, curvatura major. At the superior end of ture the esophagus enters the stomach, at the oesophageal opening, ferior end the stomach passes into the duodenum at the pylorus. ed portion to the left of the oesophagus is the fundus, while the he stomach is divisible into the body, corpus ventriculi, and the

pars pylorica. geal opening is termed the cardia, and the portion of the stomach ne pars cardiaca, while the inferior orifice is termed the pylorus, and the stomach adjacent to it is the pars pylorica, a dilated portion of

А

which forms the Fundus

antrum pyloricum Paries anterior

Cardia. — The Esophagus

opening is situated at the su

perior end of the Autrum pyloricum

lesser curvature,

on the right side _Curvatura

of the fundus,and major more on the an

terior than the Pylorus

posterior surface Ligamentum

of the stomach. gastrocolicum

Around this Sulcus intermedius

opening the muscular walls of the

csophagus and B

the mucous Ligamentum gastrolienale

membrane beParies

come continuous posterior

with correspond

ing coats of the Omentum minus

stomach wall. The longitudinal muscular coat

passes onwards Pylorus

into à longitudinal set of fibres, and the circular ceso

phageal fibres Antrum pyloricum

pass into the circular mus

cular coat. The C

whitish-coloured

stratified squamCurvatura

ous epithelium of minor Pylorus

the cesophagus is Fundus

continuous with the pinkish-coloured columnar epithelial wall of the stomach,

and the junction pyloricum

is marked by a sharp irregular line running round the margin of the opening.

The orifice Incisura angularis

itself is oval or

angular rather Paries anterior

than round, being FIG. 916. —Three Views of a Stomach fixed BY FORMALIN INJECTION IN SITU. compressed from A. From the front. B. From the back.

C. From above. side to side.
The orientation of the stomach was determined by the insertion of long pins into it in To the right

the sagittal, frontal, and transverse planes. These views show the comparatively of the orifice, the
horizontal position of the stomach associated with the horizontal posture of the
trunk. They also show the partial division into chambers produced by temporary

right margin of constrictions of the stomach wall fixed by the action of formalin.

the cesophagus

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Antrum

I a slight curve into the lesser curvature of the stomach, while on the ere is a deep notch, the incisura cardiaca, between the inferior end of gus and the fundus, in which lies a strong projecting ridge of the f the diaphragm. ich on the outer surface produces a fold in the interior of the stomach, assist in closing the oesophageal opening, and this, with the decussating diaphragm, and the strengthened circular fibres of the inferior end of the forms a kind of sphincter for this orifice which serves to prevent a from the stomach under ordinary condition. ia is very deeply placed, and lies about four inches behind the sternal eventh left costal cartilage, at a point one inch from its junction rnum. Posteriorly it corresponds to the level of the eleventh thoracic

le fixation of the esophagus by its passage through the diaphragm, and the close veen the stomach and the diaphragm, near the cardia where the peritoneum is

the most fixed part of the whole organ. The object of this immobility is iintain a clear passage for the food entering the stomach. - The pyloric orifice or pylorus is the aperture by which the stomach s with the duodenum. It is placed at the extremity of the pyloric tomach, and its position is indicated upon the surface of the stomach inular constriction which is most marked at the curvatures. is also indicated by an arrangement of blood-vessels at the pyloric ring, which is

On the peritoneal surface a thick vein passes upwards from the lower side than half-way on the anterior surface, and from the upper border a second vein rds in the same line, nearly, if not quite, meeting the first (W. J. Mayo).

ic constriction marks the junction of stomach and duodenum, and ious coats of these portions meet with one another. The peritoneal e stomach is continued onwards on to the first part of the duodenum. lorus the muscular fibres have a special arrangement, which is due ce of a mechanism for arresting the escape of food from the stomach ndergone digestion. The longitudinal fibres of the stomach (stratum are in part continued onwards into the longitudinal fibres of the but many of them bend inwards into the thickened ring around the they spread out in diverging bundles, which interlace with the most the circular fibres, and some of them reach and terminate in the lucosa. ar muscular fibres of the stomach (stratum circulare) are not ctly with those of the duodenum. On the contrary, at the orifice ery much increased in number, and they form a thick ring, or ch is separated from the circular muscular coat of the duodenum tum.

of this sphincteric ring is not easily estimated, for while it is off from the duodenum there is no sharp line of demarcation on

There the ring gradually merges into the circular muscular coat al pyloric canal. yloric canal is contracted, its wall is nearly as thick as the sphinc

mucous membrane (tunica muscosa) is continued into the mucous e duodenum at the distal margin of the sphincter. The junction ised by superficial inspection. The gastric mucosa is considerably

it covers the sphincter muscle. When examined post-mortem in y, the aperture, viewed from the duodenal side, is somewhat oval in een from the opposite side, it presents an irregular or stellate ng to the fact that the rugæ of the gastric mucous membrane are the orifice. s directed horizontally backwards, and to the right. When the however, it looks almost directly backwards, or even slightly to the

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