Images de page
PDF
ePub

e in length which takes place during distension, the pylorus is
ble distance to the right beneath the quadrate lobe of the liver,
ne time the long axis of the whole organ becomes much more
ng forwards, downwards, and to the right. Finally there is
:cial dilatation of the pyloric part, known as the antrum pyloricum,
me distension is carried so far to the right that it may even reach
ndrium.
Position of the Stomach as seen by X-Ray Examination. -Examination
1 by means of X-rays after a " bismuth meal” has given important
out the shape and position of the stomach in the living, and about
nich occur as the stomach fills and empties.
ninations corroborate, in great part, the conclusions which have been
the study of formalin specimens so far as the shape of the stomach,
in into parts, is concerned. In regard, however, to the position and
e stomach, X-rays show that the stomach in the living, and especially
attitude, is more vertical than it is after death, and when the body
n the horizontal position. In the upright position, in fact, the long
gan appears to be nearly vertical. The general shape and position
in the vertical position, moderately distended, is shown in Fig. 923.
vill be seen that not only is the body of the stomach nearly vertical,
greater curvature reaches down to the umbilicus, and may descend
it. The pyloric part is directed upwards, as well as backwards, and
not usually the lowest point of the stomach.
anatomical features of the stomach described above are well brought
he fundus is a hemispherical dome, lying to the left of the terminal
e cesophagus, and continuous in outline with the body of the stomach.
ntains gas, and appears translucent to X-rays. The body is of uniform
the pyloric part is marked off from it by the incisura angularis, on
cvature.

Further, the pyloric part shows division into pyloric antrum
anal. The incisura angularis and sulcus intermedius are distinct.
ion of the stomach is greatly influenced by attitude and by the con-
abdominal muscles. Contraction of the abdominal muscles can elevate
from 5 to 13 cm., or 2 to 5 inches, and the change from the horizontal
attitude alters the height of the inferior border from 2 to 10 cm. This
ch occurs in the alteration from the horizontal to the erect attitude,
gely for the differences found between the stomach seen in the post-
m or on the operating table and the stomach displayed by means of
nus, if the stomach figured on p. 1167 be considered fixed at the cardiac
mewhat fixed at the pylorus, and the pyloric antrum and greater
hould sink downwards, the shape, as seen from the front, would closely
e X-ray appearances found often in the living.
oty stomach is a contracted tubular organ, except at the fundus, where
co be always dilated. When food is taken, when the individual is

sitting, it runs down to the point where the gastric walls are in contact
other. The distal portion of the stomach dilates for some distance, or
far as the pyloric canal.
stomach becomes filled the whole of the body of the organ becomes
the fundus and cardiac portion more particularly so, and these two latter
as a storehouse.
s no definite division of this portion from the remainder of the stomach
anent sphincter, but the peristaltic waves of contraction begin about the
the organ, and form a fleeting constriction between the two parts.
istalsis goes on, the tubular pyloric part relaxes somewhat. The waves
sis here become so deep as to divide this portion into chambers. The
ances are forced through the pylorus by successive waves of peristalsis,
e form, usually, of jets which impinge against the posterior aspect of
nal wall.
I there be undigested masses, the pyloric valve relaxes to allow them also
to the duodenum.

[ocr errors]
[graphic]

се ariia, а
e looped
Tands the
Tas they
* givic
acter wh
2 a thick m

The fire
a layer,
- arranged
seot Parts

sme m

Tunica mucosa

ayerا ملا۔

Fine part

STRUCTURE OF THE STOMACH.
The stomach wall is composed of four coats—namely, from without inwards : (1)
Tunica serosa, (2) tunica muscularis, (3) tela submucosa, and (4) tunica mucosa (Fig. 924).
Tunica Serosa.—The serous coat is formed of the peritoneum, the relations of which

to the stomach have already been described. It is
closely attached to the subjacent muscular coat,
except near the curvatures, where the connexion
is more lax; and it confers on the stomach its
smooth and glistening appearance.

Tunica Muscularis. —The muscular coat, which
is composed of unstriped muscle, is thinnest in the
fundus and body, much thicker in the pyloric
portion, and very highly developed at the pylorus.

It is made up of three incomplete layers -- an submucosa

external, stratum longitudinale; a middle, stratum
circulare; and an internal of oblique muscular fibres,

fibre obliquc. Stratum

The stratum longitudinale consists of longitucirculare

dinal fibres, continuous with those of the esophagus
on the one hand, and those of the duodenum on
the other (Fig. 926, A). They are most easily

demonstrated on the lesser curvature, where they
Stratum
longitudinale

can be traced down from the right side of the
@sophagus. Over the greater curvature and on the
two surfaces they are present as an extremely thin

and irregular sheet. Towards the pylorus the longiTunica serosa

tudinal fibres grow much thicker, and also much

tougher and more closely united, and they take part Fig. 924.—TRANSVERSE SECTION THROUGH in the formation of the pyloric valve. THE WALL OF A HUMAN STOMACH.

x 250.

A specially condensed band of these can be often made out both on the front and back at the antrum pyloricum, the form of which is said to be due to their presence. These bands are known as the ligamenta pylori (pyloric ligaments).

[graphic]

They are 2 deeper cir OT End of tb

aped bus e comach i

:he cardia, awards as

derabled f the organ. they pass wine less o ries which be stomai

the s sobique fil

by remc 7. either sur a traced

be found 71 and joi

[graphic][subsumed][subsumed][subsumed]

calar layer.

Tela Sul
We coat i
Die oonnect
Teen and u

Is chats swis attache - re closely to

[merged small][merged small][ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]
[ocr errors]

Fig. 925.- MUSCULAR COAT OF THE Stomach, seen from within after removal of the mucous and submucous

layers. The anterior half of the stomach is shown, viewed from behind (Cunningham). The stratum circulare is composed mainly of circular fibres, continuous with the more superficial of the circular fibres at the lower end of the wesophagus (Fig. 925). They begin as a set of U-shaped bundles which loop over the lesser curvature at the right of

[ocr errors]

pass downwards and to the left on both surfaces. Further to the right es are succeeded by circles which surround the organ completely. Traced row end of the stomach, the circular bundles grow thicker, and at the ndergo a further inrise to the pyloric

surrounds the orifice ular ring. bliquæ, forming the nsist of fibres which

the fundus and adthe stomach, in much ner as those of the are on the body and

the organ (Fig. 926, continuous above with ular fibres of the ine æsophagus, and form dles which loop over mmediately to the left and run very obliquely d to the right for a stance on both surfaces

These looped fibres, to the left, gradually blique, and finally form surround the wide end ch completely, even as ummit of the fundus. bres can be most readily oving the circular fibres rface below the cardia. towards the right, they to terminate by turning ining the fibres of the

[graphic]
[graphic]
[graphic]

С

abmucosa. The sub

is a layer of strong but ctive tissue, which lies

unites the muscular and s (Fig. 924). It is more hed to the muscular and

to the mucous coat, and bed in which the vessels break up before entering

membrane. Mucosa.—If examined in ate soon after death, the at is of a reddish-gray Fig. 926. —The Three LAYERS OF The Muscular Coat of of moderate consistence.

THE STOMACH. A, External or longitudinal layer; B, mined some time after

Middle or circular layer; C, Internal or oblique layer. colour turns to a darker a, Longitudinal fibres of cesophagus ; b, Superficial circular the whole membrane be- fibres of csophagus passing into circular fibres of stomach

in B ; c, Deep circular fibres of oesophagus passing into er and more pulpy. It is

oblique fibres of stomach in C; d, Oblique fibres forming er 2 mm.) and firmer in

rings at the fundus; e, Submucosa. than in the cardiac part, onest at the fundus, where it often shows signs of post-mortem digestion.

stomach is empty all three outer coats, which are extensile, contract; whilst ensile mucous coat, as a result of its want of elasticity, is thrown into prominent folds or ruge, which project into the interior and, as it were, occupy of the contracted organ. These are, in general, longitudinal in direction, erous cross branches, and they are largest and most numerous along the urvature. They disappear when the stomach is distended. the surface of the mucous coat is examined in a fresh stomach, it is seen to

[graphic]
[merged small][merged small][merged small][ocr errors][ocr errors][merged small]

be marked out into a number of small, slightly elevated, polygonal areas, arece gastrice, by numerous linear depressions; the mucous membrane is consequently said to be mamillated (Fig. 927, À). These little areas, which measure from 1 to 6 mm. in diameter, are beset with numerous small pits, foveolæ gastricæ, about 2 mm. wide, which are the mouths of the gastric glands, and they are so closely placed that the amount of surface separating them is reduced (particularly in the pyloric portion, where the gland mouths are widest) to a series of elevated ridges, plicæ villosa, resembling villi on section. Although the gland mouths cannot be seen with the naked eye, a very slight magnification is sufficient to show them clearly ; it is also possible to see the gland tubes leading off from the bottom of each (Fig. 927, B).

Minute Structure of the Mucous Coat. - In structure the mucous coat consists of an epithelial covering composed of long columnar cells, and of numerous tubular glands, glandula

gastrica, which are prolonged out-
wards from this surface, and which
are enclosed in a delicate connective

tissue stroma, with some small lymph Rugæ

nodules, noduli lymphatici gastrici.
The bases of the glands reach out-
wards to the lamina muscularis

mucosa, a layer consisting of an ex. Mamilla

ternal longitudinal and an internal
circular layer of plain muscle fibres

Glandulæ Gastricæ.—These con-
sist of a duct terminating in one or
more secreting tubules. The duet is
lined with columnar epithelial cells,
similar to those which cover the sur-
face of the mucous membrane. Three
varieties of glands are found in dif-

ferent regions of the stomach, and Mouths of gastric glands,

are named from their positionwith gland

(1) Cardiac Glands. — These tubes at

glands are situated close to the resobottom

phageal opening. The duct terDepression

minates in a single long tubule, between two

which is lined with short columnar mamillæ

granular cells.

(2) Fundus Glands.- In these Mouth of

Pod glands the duct terminates in one gastric gland

or more tubules, lined with polyB

hedral cells, termed the chief or cenFig. 927.-Mucous MEMBRANE OF THE STOMACH. A, Natural ţral cells

. At intervals, between this size ; B, Magnified 25 diameters. In A the rugze and the layer of cells and the basement memmamillated surface are shown. In B the gland mouths brane, are placed larger spheroidal (foveolæ gastricæ), with the gland tubes leading off from some cells, which stain more deeply as a of them, and the ridges separating the mouths (plicae villose) rule, termed the parietal or oryntic are seen.

cells. These glands are found in the

fundus and body of the stomach. (3) Pyloric glands are found in the pyloric portion of the stomach. These consist of a short duct

, terminated in a group of short but tortuous gland tubules. These tubules are lined with short columnar or polyhedral cells, similar to the central cells of the fundus glands.

Blood-vessels.---The arteries of the stomach are all derived ultimately from the cæliac artery The gastric artery arises from this trunk direct. Having reached the lesser curvature and given of an oesophageal branch, it divides into two large branches

, which run, one on each side of the organ, along this curvature, and join below with two similarly-disposed arteries derived from the right gastric branch of the hepatic. From the two arches thus formed, four or five large branches pass to each surface of the stomach, and soon pierce the muscular coat. Along the greater curvature several smaller branches reach the stomach from the right and left gastro-epiploic arteries, which are branches respectively of the gastro-duodenal and the splenic, and run in the gastro-colic ligament close to its attachment to the stomach. Finally, four or five short gastric arteries, branches of the splenic, are distributed to the fundus of the stomach, which they reach by passing forwards between the layers of the gastro-lienal ligament. At first the arteries lie beneath the peritoneum ; very soon, however, they pierce the muscular coat, which they supply, and, reaching the submucosa break up to form a close network of vessels. From these arise numerous small branches, which enter the mucous membrane and form capillary plexuses around the glands as far as the surface.

The veins begin in the capillary plexuses around the glands ; uniting, they form a networš in the submucosa, from which arise branches that pierce the muscular coat, and finally end in the following veins: the right gastro-epiploic, which joins the superior mesenteric; the left gastroepiploic, and four or five veins corresponding to the short gastric arteries, which join the splenie; the coronary vein of the stomach, which runs along the lesser curvature from left to right, and joins

The smal cween the 2 pylorus

, eli by joini bdominal ca abilical, hy

regions In length **tes, it is reath at 24 Ting from

mm.) at t

a the py

[ocr errors][merged small][ocr errors][ocr errors][merged small][ocr errors][ocr errors][merged small][merged small][merged small][merged small]

ds.

e veins contain numerous valves which, though competent to prevent the child, are rarely so in the adult. s of the stomach arise in an extensive plexus in the mucous membrane

They then join a plexus of vessels in the tela submucosa, from which atervals to join another plexus of vessels, subserous in position; piercing iquely in their course. The efferent vessels pass mainly from the subserous zed in three main groups, which pass in different directions, and drain f the stomach wall. is connected mainly with the whole of the lesser curvature, from fundus adjacent half or two-thirds of the anterior and posterior surfaces of the els pass to the superior gastric glands, along the lesser curvature, and, in

gastric artery, to the cæliac glands. f vessels drains an area which includes the greater curvature below the -cent portions of the anterior and posterior surfaces of the stomach. These = right gastro-epiploic artery to some inferior gastric glands which lie below rus, and thence they pass with the hepatic artery to the cæliac glands. vessels drains the region of the fundus. The vessels from this area pass in gament to the spleen, where they are connected with some splenic glands, long the superior border of the pancreas, to the cæliac glands also. d inferior gastric glands and the splenic glands are the first glands interposed e lymph vessels. The coeliac glands form the second set. e derived from the two vagus nerves and from the cæliac ganglia of the e vagi nerves pass through the diaphragm with the esophagus, the left or, the right on its posterior aspect; in this way they reach the anterior and of the stomach respectively. Here they unite with the sympathetic fibres from which pass to the stomach with the branches of the cæliac artery: The nerve chiefly non-medullated, form two gangliated plexuses, those of the myenteric bmucous plexus, in the muscular and submucous coats respectively. hent of the stomach is described with that of the intestines on pp. 47 and 1249.

INTESTINUM TENUE.

1 intestine is the portion of the digestive tube which is placed stomach and the beginning of the large intestine. It commences at

where it is continuous with the stomach, and ends at the valvula ing the large intestine. It occupies the greater portion of the avity below the liver and stomach (Fig. 913), and is found in the ypogastric, and both lumbar regions; also, but to a less extent, in the as of the abdomen, and in the pelvic cavity. th, the small intestine usually measures over 20 feet. According to

221 ft. in the male, 23 in the female, whilst Jonnesco gives the average 24 ft. 7 ins., or 71 metres. In form it is cylindrical, with a diameter om nearly two inches (47 mm.) in the duodenum to a little over an inch at the end of the ileum; there is thus a gradual diminution in its size pylorus to the valvula coli. all intestine is relatively longer in the child than in the adult; at birth it is to the total he child as 7 to 1, whilst in the adult the proportion is as 4 to 1. Notwithstanding ults, it is generally held that the small gut is relatively longer in the male than the the former figures, 20 to 22 feet, represent the entire length of the intestine in its most form, after death, when muscular tonus has disappeared, it is probable that during life h is not so great. The muscular coats, both longitudinal and circular, are more or less d, and probably the total length during life may be estimated as 15 toʻ17 feet. rmalin-hardened bodies the small bowel rarely measures more than 12 or 13 feet in

Similarly its diameter is often reduced in places to į or 4 inch (12:5 to 18.7 mm.), o the greater part of the gut may retain its usual width : these narrow parts have tly been fixed in a state of contraction. ne small intestine is divided more or less arbitrarily into three parts (Fig. 873) nely, the duodenum, constituting the first eleven inches, distinctly marked off the rest by its fixation and the absence of a mesentery; the intestinum jejunum pty intestine") which comprises the upper two-fifths, and the intestinum ("twisted intestine") the lower three-fifths of the remainder. The jejunum Ileum pass imperceptibly into one another, and the line of division drawn between n is entirely artificial; however, if typical parts of the two-namely, the inning of the jejunum and the end of the ileum—are selected, they differ so

« PrécédentContinuer »