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is simply to pull the cæcum out of the wound, and if the parts are normal the process will be delivered along with it; if, on the other hand, the cæcum and the vermiform process are tacked down by adhesions, the vermiform process is best discovered by following the anterior tænia coli to the root of the process.
Ascending Colon.--The ascending colon, after crossing the iliac crest, lies deeply ha in the right lumbar region upon the fascia covering the quadratus lumborum and the adjacent aponeurotic origin of the transversus abdominis. Between the bowel and the fascia is a quantity of loose cellular tissue and fat, which may be the seat of a large abscess, secondary, (1) more especially, to disease of the colon itself, (2 war to disease of a retro-colic vermiform process, or (3) to disease of the right kidney This cellular tissue is directly continuous above with a thin layer lining the inferiorem surface of the diaphragm; hence the suppurative process may extend upwards giving rise to one form of subphrenic abscess. In some cases the ascending colon is i completely surrounded by peritoneum, and it may even be provided with a distinct mesentery. The latter condition is almost invariably present in infants suffering Pe from extensive ileo-cæcal intussusception. After the invagination has been reduced the mesentery proper is seen to be continuous, through the ascending das mesocolon, with the mesentery of the transverse colon.
In order to resect the ascending colon the surgeon mobilises it by dividing the peritoneum along its line of reflection from the lateral aspect of the colon on to the abdominal wall. The colon, along with the posterior peritoneum medial to it. is then stripped, from the lateral side towards the median plane, off the quadratus lumborum, the psoas, and the inferior pole of the right kidney. While this is being done, the branches of the ileo-colic and right colic vessels which pass laterally to supply the gut are secured, and the lymph vessels and associated lymph glands are removed along with the bowel. As the peritoneum is stripped off, care must be taken not to injure the important structures which lie behind it, namely, the duodenum, the ureter, and the spermatic vessels.
The right colic flexure reaches upwards beneath the tenth costal cartilage into the most inferior part of the right hypochondrium, where it lies immediately to the right of the gall-bladder, between the liver and the inferior half of the anterior surface of the kidney. Posteriorly, it is separated from the anterior surface of the right kidney by a quantity of loose cellular tissue; hence by dividing the peritoneum to the right side of the flexure it can readily be mobilised and separated from the kidney.
Transverse Colon.-The transverse colon crosses the lower part of the umbilical region immediately below the greater curvature of the stomach. In cases of chronic constipation it may form a U-shaped or V-shaped loop, extending down to the level of the pubes. When this is the case the natural kinking at the right and left coli. flexures becomes more acute, and tends, therefore, to aggravate the constipation. In such cases the right and left portions of the transverse colon often lie parallel and close to the ascending and descending colon, respectively, like the barrels of a gun
The transverse colon receives its blood-supply from the arch formed by the middle and left colic arteries. The arch lies in the posterior wall of the bursa omentalis between the two layers of the transverse mesocolon. In resecting portions of the stomach for malignant disease, the surgeon removes also the glands which lie between the two layers of the gastro-colic ligament in relation to the right gastro-epiploic vessels. At this step of the operation care must be taken not to endanger the blood-supply of the transverse colon by injuring the middle colic artery The left colic flexure is more acute and more fixed than the right flexure; and it is situated at a higher level as well as more deeply. A tumour originating in this portion of intestine lies generally under cover of the left costal margin, and is therefore difficult to palpate. To expose the left colic flexure, the omentum along with the transverse colon and the body of the stomach is turned upwards. mobilise it for the purpose of resection the surgeon must divide: (1) the phrenicocolic ligament, which attaches it to the diaphragm opposite the eleventh rib; (2 the left border of the greater omentum, which attaches it to the stomach; (3) the left portion of the transverse mesocolon, which attaches it to the lets extremity of the pancreas.
Descending Colon.-The descending colon, like the ascending, is deeply placed in the lumbar region and is related to the inferior half of the lateral border of the left kidney. It is less frequently provided with a mesentery than is the ascending colon.
Iliac Colon. The iliac colon commences at the junction of the posterior and middle thirds of the iliac crest, and ends at the superior aperture of the pelvis minor by joining the pelvic colon. It possesses no mesentery and is connected to the fascia covering the iliacus and psoas major muscles by loose areolar tissue. Towards its termination it turns medially immediately above and parallel to the inguinal ligament, and at its junction with the pelvic colon it lies in front of the external iliac artery. Although, as a rule, it is entirely overlapped by coils of small intestine, it can frequently be felt by firm palpation at the lateral part of the left iliac fossa, because its muscular wall is comparatively thick and generally contracted.
Pelvic Colon. The pelvic colon, in consequence of possessing a well-developed mesentery, forms a freely movable loop which, though usually confined to the pelvis minor, may, when distended, rise well up into the abdomen. It is this section of the large intestine which is opened for the purpose of making an artificial anus in malignant disease of the rectum.
The pelvic colon varies considerably in length, the average being sixteen or seventeen inches. It is relatively longer and of greater calibre in the child than in the adult. It is the part of the large intestine especially involved in the condition known as megalocolon or Hirschsprung's disease-a congenital abnormality in which the large intestine is greatly dilated and hypertrophied.
When the pelvic colon is thrown upwards and to the right so as to spread out its mesentery, the latter is seen to be attached in an inverted V-shaped manner to the posterior wall of the pelvis. At the apex of the V is a small peritoneal pouch the inter-sigmoid fossa, situated just in front of the ureter as it crosses the termination of the common iliac artery to enter the pelvis minor. This fossa is one of the situations at which an internal retro-peritoneal hernia may originate. The mouth of the fossa looks downwards and to the left, while above and to its right is the sigmoid artery. The fossa affords a guide to the commencement of the pelvic portion of the left ureter. On account of the V-shaped attachment of this mesentery it is convenient to speak of the pelvic colon as possessing an ascending or proximal and a descending or distal limb. At the junction of the proximal limb with the termination of the iliac colon is a more or less well-marked flexure (the "last kink" of Arbuthnot Lane). It is to the proximal limb of the pelvic colon that the divided inferior end of the ileum is anastomosed in the short-circuiting operation of ileo-sigmoidostomy.
In the author's operation of transplanting the ureters into the large intestine for incontinence of urine, the result of epispadias in the female, and of ectopia vesicæ in either sex, the left ureter is implanted into the ascending limb of the pelvic colon and the right ureter into its descending limb.
By dividing the attachment of the mesentery of the pelvic colon in the operation of excision of the rectum, the pelvic colon may be mobilised sufficiently to allow of its being brought down and sutured to the skin in the sacral region or even to the anal region. Further, the mobility of the pelvic colon is such that after resection of the descending and iliac colon and mobilisation of the left colic flexure, the divided ends of the bowel can be sutured together without undue traction.
After operations on the female genital organs by the abdominal route-for example, after abdominal hysterectomy-the surgeon makes use of the pelvic colon and its mesentery by spreading them out over the pelvis so as to roof it in, and so prevent any of the coils of small intestine from becoming adherent in the pelvis.
Kidneys. The kidneys lie behind the peritoneum, and extend higher up than is often supposed, and laterally they do not extend so far away from the vertebral column as is almost invariably depicted; hence it is that, unless enlarged, the kidneys can seldom be felt through the abdominal wall. The right kidney as a rule lies a
little lower than the left, as well as a little further away from the median plane. The hilum of the right kidney lies 2 in. from the median plane; that of the left 11⁄2 in. from the median plane. For practical purposes the hilum of the kidney may be regarded as opposite a point on the anterior abdominal wall a finger's breadth medial to the tip of the ninth costal cartilage; and a line joining the two hila crosses the vertebral column opposite the fibro-cartilage between the first and second lumbar vertebræ, that is to say, a little below the transpyloric line. The highest point of the kidney is situated two inches from the median plane, on a level with a line crossing the abdomen midway between the xiphisternal and transpyloric planes. The lowest point of the kidney reaches down to, or a little below, the infra-costal plane.
The student should make himself familiar with the feel of the parts in relation to the kidneys, as far as they can be made out by introducing the hand through a median abdominal incision.
The superior half of the anterior surface of the right kidney is felt, at the bottom of the hepato-renal peritoneal pouch, by passing the hand deeply into the right hypochondrium, between the anterior margin of the liver and the right flexure of the colon. The inferior half is palpated by passing the hand deeply into the highest part of the right infra-colic peritoneal compartment; its free peritoneal surface lies in the angle of the right flexure of the colon. The second portion of the duodenum overlaps both the supra- and infra-colic portions of the medial border of the right kidney. When the right kidney is excised by the abdominal route, the peritoneum is divided lateral to the ascending colon and right colic flexure, and these structures, along with the descending part of the duodenum, are stripped off the organ in a medial direction, until the hilum and the renal vessels are reached.
The left kidney is crossed transversely, about its middle, by the body of the pancreas and the splenic vessels. To palpate the supra-pancreatic portion, the hand is passed through the left portion of the gastro-colic ligament, upwards behind the stomach, into the superior part of the omental bursa. The spleen will be felt to overlap the lateral border of the kidney. To palpate the infra-pancreatic portion of the organ, which is covered by the peritoneum continued downwards from the attachment of the inferior layer of the transverse mesocolon, the hand is passed deeply into the upper part of the left infra-colic peritoneal compartment as far as the angle of the left flexure of the colon. This area of the kidney is overlapped by coils of small intestine, while passing transversely laterally in front of it are the left colic artery and its branches. When the left kidney is excised by the transperitoneal route, the left colic flexure and the descending colon are mobilised by dividing the peritoneum lateral to them so as not to injure the left colic artery.
In addition to their true fibrous capsules, the kidneys are surrounded by and enveloped in a well-marked fatty capsule. Outside this perinephric fat is a more or less well-defined fibrous envelope, known as the renal fascia or fascia of Gerota, which forms, as it were, a sheath to the organ. Hence, just as in the case of the prostate and thyreoid glands, the kidney possesses, in addition to its true capsule, a sheath derived from the neighbouring fascia. The anterior and posterior layers of the sheath remain distinct at the medial border of the kidney and are prolonged, the one in front of, and the other behind the renal vessels. The two layers remain separate also for some distance below the inferior pole of the kidney, and it is into this downward extension of the fascial compartment that the kidney descends in the condition known as movable kidney. Above and laterally the sheath joins the fascial lining of the diaphragm and transversus muscles respectively. Outside the perinephric fascia is a second layer of fat sometimes spoken of as the paranephric fat.
When the inferior pole of the kidney receives a special blood supply, either directly from the aorta, or from the renal artery, the abnormal vessel may, by passing either in front or behind the superior part of the ureter, cause the latter to be so kinked over the vessel as to cause a secondary hydronephrosis.
Brodel has shown that the branches of the renal artery are distributed to the cortex of the kidney in an anterior and a posterior group; hence, in splitting the
kidney substance to reach the renal pelvis, the incision should be made along the frontier line between the two vascular areas, viz., about half an inch behind and parallel to the lateral border of the kidney.
The ureters lie behind the peritoneum covering the psoas major muscles; the descend almost vertically in the umbilical region 1 in. from the median plane. At the level of the intertubercular plane they lie in front of the termination of the common iliac arteries, and then pass down into the pelvis minor, in front of the hypogastric arteries.
The ureter possesses a well-developed muscular wall so that it is well adapted for suturing, while its rich blood supply favours rapid healing. Its abdominal portion is supplied by the renal and internal spermatic arteries; its pelvic portion by the superior vesical, the inferior vesical, and the middle hæmorrhoidal arteries. By their anastomosis they form a continuous and somewhat tortuous chain which: generally visible beneath the peritoneum along the whole course of the tube.
In reading skiagrams with a view of ascertaining the presence or absence of calculi in the abdominal portion of the urinary tract, Hurry Fenwick makes use of a line projected vertically upwards from the highest part, i.e. the centre, of the iliac crest to the twelfth rib. As this line corresponds to the lateral limit of the kidney, it follows that a "calculus shadow" close to the medial side of this line will generally occupy one of the calyces and be situated, therefore, towards the cortex, while if the shadow be situated close to the tips of the transverse processes of the vertebræ, the calculus will usually be found either in the pelvis of the kidney or in the abdominal portion of the ureter. The other points to be kept in mind in reading the radiogram are that the pelvis of the kidney lies opposite the interval between the transverse process of the first and second lumbar vertebræ, and secondly, that the abdominal portion of the ureter descends in the line of the tips of the transverse processes of the second, third, fourth, and fifth lumbar vertebra.
Pancreas. The head of the pancreas occupies the curve of the duodenum, and lies in the lowest part of the right half of the epigastric region, on a level with the second lumbar vertebra. The neck, which crosses the median plane opposite the fibro-cartilage between the first and second lumbar vertebræ, lies in the transpyloric plane, while the body lies immediately above that plane. The tail lies in the left hypochondriac region. The relations of the pancreas to the transverse mesocolon and to the neighbouring viscera have already been sufficiently referred to.
After opening the abdomen in the median line, the pancreas is best exposed by passing through the gastro-colic ligament; access to the organ through either the hepato-gastric ligament or the transverse mesocolon is more limited and therefore less satisfactory.
A pancreatic cyst gives rise to a tumefaction of the abdomen either in the epigastric or in the umbilical region, depending on whether it pushes the hepatogastric ligament before it and develops between the liver and stomach, or whether it extends forwards below the stomach. In severe contusions of the abdomen the pancreas may be ruptured against the vertebral column.
Vessels of the Abdomen. The commencement of the abdominal aorta and the coeliac artery are situated two fingers' breadth above the transpyloric plane. The superior mesenteric artery arises a finger's breadth above the transpyloric plane, the renal arteries a finger's breadth below it. The inferior mesenteric artery arises midway between the transpyloric and the intertubercular plane--that is to say, about 1 in. above the level of the umbilicus. The abdominal aorta bifurcates in, or a little to the left of, the median plane, on a level with the highest part of the iliac crest, and about in. below the level of the umbilicus.
The inferior vena cava lies immediately to the right of the aorta; its most important surgical relation is the right ureter, which lies close to its right side.
The common and external iliac arteries may be mapped out by drawing a line. curved slightly laterally, from a point opposite the bifurcation of the aorta to 3 point midway between the superior anterior iliac spine and the pubic symphysis. the superior third of this line corresponds to the common iliac, the inferior twothirds to the external iliac.
In ligaturing the common iliac artery, or the superior part of the external iliac,