Diseases of the intestines; a text-book for practitioners and students of medicine

Front matter

Class JS&1M Book J

GopyrightN

COPYRIGHT DEPOSIT.

Preface To The Second Edition

It affords me much gratification to see that my work on " Diseases of the Intestines " has found favor with the medical profession. The entire issue being exhausted, a new edition of this book is herewith published. Yery few additions have been made to the original text, as the progress in this branch of medicine within the last four years has been but scanty. I trust the present edition will meet with the same friendly reception as the first.

Max Einhorn.

New York, February 10th, 1904.

Preface To The First Edition

This treatise is a continuation of my work on "Diseases of the Stomach," the two together comprising the principal disorders of the digestive tract. In discussing the subject of the intestinal affections an effort has been made to follow the same lines laid down in my book on the stomach. The practical points regarding diagnosis and treatment are always placed in the foreground.

Although onr knowledge of diseases of the intestines has not made such rapid progress as that of morbid conditions vi PREFACE.

of the stomach, much has likewise been achieved in this field. Surgery has made many successful advances. The elucidation of the intimate relation existing between functional disturbances of the stomach and of the intestines also marks an important step forward, especially as to therapy.

While there are many excellent works on intestinal diseases by- German authors, the more recent English literature contains no monographs on this important subject. The medical encyclopedias, it is true, contain very instructive contributions on this topic, and among these Ewald's treatise on diseases of the intestines in the "Twentieth Century Practice of Medicine " is a most valuable acquisition.

The present volume, it is hoped, will to a certain extent fill the void in American literature of a monograph on the affections of this portion of the digestive tract. The writer desires to express his indebtedness to Nothnagel, Eoseuheim, Boas, Fleischer, Ewald, Pick, Fowler, Treves, and Ailingham, whose works have been frequently consulted. He trusts that this book will prove of practical utility to the practitioner, and if it will aid him in more successfully treating this class of cases, the author's effort will be more than recompensed. MAX Einhorn.

New York, April, 1900.

CHAPTER I. Anatomy and Physiology

PAGE

The Intestinal Canal (Intestinum), 1

The Duodenum, . .1

The Small Intestine, 4

Structure of the Small Intestine, ..... 6

The Large Intestine or Large Bowel (Intestinum Crassum), . 11

Histology of the Large Bowel, 17

1. The Secretory Function or the Chemical Processes in the

Intestines, 18

2. Absorption 24

3. Motion, 28

CHAPTER n.

Methods of Examination and Treatment.

Interrogation, 32

Inspection, 34

Proctoscopy, . 37

Palpation, 40

Percussion, 44

Auscultation, 45

Inflation of the Intestine with Carbonic Acid Gas or Air, . 45

Injection of Water per Anum, 48

Lavage of the Bowel, 48

Examination of the Faeces, 49

Diet, t . . 77

Mechanical Procedures, . . 81

Injections 81

Massage and Gymnastic Exercises, . . . . .83 vm . CONTENTS.

PAGE

Mechanical Procedures:

Hydrotherapy, 83

Electricity, 84

CHAPTER HI.

Acute and Chkonic Intestinal Catarrh.

General Subjective Symptoms, 90

Objective Symptoms, . 91

Fever, 92

Localization of the Catarrhal Process, 92

Objective Symptoms, 102

Hydrotherapeutic Measures, 109

Mineral Waters, 110

CHAPTER IV.

Dysentery.

CONTENTS.

IX

Symptomatology of Acute Dysentery, Symptomatology of Chronic Dysentery

Complications, . . .

Treatment of Acute Dysentery, Treatment of Chronic Dysentery,

PAGE

. 123

. 126

. 127

, 127

, 128

CHAPTER V.

Ulceus of the Intestines.

. 133

. 133

. . .133

. 133

Morbid Anatomy, .......

. 134

Situation of the Ulcer,

. 135

. 136

. 138

Diagnosis, ........

. 138

. 139

Treatment, ........

. 139

2. Embolic and Thrombotic Ulcers, . .

. 140

Pathological Changes, ......

. 140

. 141

Diagnosis, ... .

. 143

. 144

Treatment, ........

. 144

3. Amyloid Ulcers, ........

. 145

Diagnosis, ........

. 146

4. Tuberculous Ulcers, . ......

. 146

5. Syphilitic Ulcers, ........

. 149

6. Toxic Ulcers,

. 150

Symptomatology, ........

. 151

Diagnosis, ..,.♦,..

. 153

. 153

. 153

CHAPTER VI.

Neoplasms of the Intestine.

. 156

. 156 x CONTENTS.

PAGE

Cancer :

Sarcoma and Lympho-Sarcoma, . . . . . .172

Benign Tumors of the Intestine, 173

CHAPTER VII.

Hemorrhoids.

Radical, 191

Prolapse of the Rectum, . . 195

Fissure of the Anus, . . 199

CHAPTER VIII.

Appendicitis.

Differential Diagnosis, 221

CONTENTS. xi

PAGE

Medical, 224

Surgical, 227

CHAPTER IX.

Intestinal Obstruction.

Introductory Remarks, 232

Acute Intestinal Obstruction, 233

Compression of the Intestine, 233

Strangulation by Adhesions, 234

Strangulation by Meckel's Diverticulum, . . . 236

Volvulus, 238

Obturations, 239

Intussusception, 240

Pathological Changes, 242

Objective Signs, 251

Medical, 264

Surgical, 272

Chronic Intestinal Obstruction, 272

Course and Prognosis, 283

Operative Intervention, 286

CHAPTER X.

Nervous Affections of the Intestines.

Motor Neuroses of the Intestines, 290

Diarrhoea, 290

Etiology and Symptomatology, 290 xii CONTENTS.

PA.3E

Diarrhoea :

Moral, 311

Dietetic, . . . 311

Mechanical, 312

CHAPTER XL

Nervous Affections of the Intestines.

Motor Neuroses (Continued), 320

Paralysis of the Intestines, 320

Proctospasmus, or Spasm of the Rectum, 322

Paresis and Paralysis of the Sphincters of the Anus, . . 323

Peristaltic Restlessness of the Intestines, 325

Etiology and Symptomatology, 325

Sensory Neuroses of the Intestines, ■ . . . . . .331

CONTENTS. xiu

PAGE

Hypogastric Neuralgia, 338

Hyperesthesia, Paresthesia, and Anaesthesia of the Intestine, 339

Secretory Neuroses of the Intestines, 341

History, 341

Intestinal Neurasthenia, 353

CHAPTER XII.

Intestinal Parasites.

Protozoa, 355

Amoebae, 355

Sporozoa, 356

Infusoria, 356

Vermes, 357

Cestodes (Tape Worms), 357

Taenia Solium, 360

Taenia Saginata or Mediocanellata, 361

Bothriocephalus Latus, Taenia Lata, or Pig Head, . , 363

Taenia Nana, . 364

Taenia Cucumeriua, 364

Taenia Flavopunctata or Taenia Diminuta, . . . 365

Trematodes (Fluke Worms), . 368

XIV CONTENTS.

PAGE

Trematodes (Fluke Worms) :

Distoma Hepaticum or Liver Fluke, . . . . . 3^8

Distoma Lanceolatum, 3(59

Distoma Haematobium or Bilharzia Hsematobia, . . 370

Nematodes (Round Worms), 371

Ascaris Lumbricoides (Common Spool or Round Worm), . 371

Ascaris Mystax, 375

Oxyuris Vermicularis, Awltail, Seat or Pin Worm, Maggot

or Thread Worm, 375

Anchylostoma Duodenale, Dochmius Duodenalis, or Stron-

gylus Duodenalis, 378

Anguillula Stercorals, 382

Anguillula Intestinalis, 382

Trichocephalus Dispar, Whip Worm, .... 383

Trichina Spiralis, . . . . .... 385

DISEASES OF THE INTESTINES.

CHAPTER L

ANATOMY AND PHYSIOLOGY.

ANATOMY.

The Intestinal Canal (Intestinum).

The intestinal canal may be divided into two parts, the small intestine and the large intestine (Fig. 1). The small intestine (intestinum tenue) is about seven to eight metres long, the first portion being called the duodenum, the second the jejunum, and the third the ileum. With the exception of the duodenum the small intestine lies for the most part inside the more fixed portion of the large intestine and is connected to the posterior abdominal wall by the mesentery. This broad membrane extends from above downward and from left to right, from the end of the duodenum above to the ileocecal valve below, enclosing the jejunum and ileum along the whole of their extent.

The Duodenum.

The duodenum, so called on account of its length (being

about twelve inches long), is, unlike the other parts of the

small intestine, very definite in position and extent. It is

that part which is not suspended by the mesentery. It is,

further, the most fixed as well as the widest part of the

small intestine, measuring one and one-half to two inches 1

* DISEASES OF THE INTESTINES.

in diameter. It has a curved shape, somewhat resembling that of a horseshoe. It surrounds the pancreas and is divided into four parts :

1. The superior horizontal portion (pars horizontalis superior) begins at the pylorus, lying at the level of the first lumbar vertebra, and runs slightly upward and backward toward the right until it reaches the right side of the vertebral column. It ends at the neck of the gall bladder, and is the most movable of the four portions. It is covered by the two layers of the peritoneum which are continued from the stomach, and by these it is completely surrounded. Above it lie the liver (quadrate lobe) and the gall bladder, below it is the pancreas, and behind it are the common bile duct and hepatic vessels.

2. The descending portion of the duodenum, beginning at the neck of the gall bladder, is about twice as long as the first portion, and runs almost vertically to the second or third lumbar vertebra. It lies to the right of the lumbar vertebrae, and touches the right kidney. In front of it and crossing it almost at a right angle, runs the transverse colon. It is more fixed than the first portion. On its left side is the pancreas, and the common bile duct a little more posteriorly. Into this part of the bowel, and at its inner and back part, but four inches from the pylorus, the common bile duct and pancreatic duct enter. The portion at which these ducts enter, occasionally forms a small sinus (diverticulum or ampulla Yateri).

3. The third part or the transverse portion is the longest, measuring about five inches. It extends from the base of the second or third lumbar vertebra on the right side obliquely across the spine to the upper part of the left side, ascending a little on its way. In front of it is found the lower layer of the transverse mesocolon. The superior mesenteric vessels cross this part of the duodenum, running between it and the pancreas in order to reach the mesentery. This portion is in relation with the pancreas and superior

Fig. 1.— The Intestine, as Seen from the Front, after Removing the Omentum (Testut). 1, Abdominal wall ; 2, wall of the thorax ; 3, oesophagus ; 3', cardia ; 4, stomach ; 4', pylorus ; 5, duodenum ; 6, pancreas ; 7, liver ; 8. gall bladder ; 9, gastrohepatic ligament ; 10, right kidney and its suprarenal capsule ; 11, small intestine ; 12, terminal portion of the ileum ; 13, caecum ; 13', its appendix ; 14, ascending colon : 15, transverse colon ; 16, descending colon ; 17, ileopelvic colon ; 18, bladder ; 19, parietal peritoneum ; 20, spleen ; 21, diaphragm ; 22, thoracic aorta.

Mesenteric artery above, with the vena cava, aorta, and crura of the diaphragm behind. It is the most fixed portion of the duodenum.

4. The fourth part of the duodenum or second ascending portion ascends vertically at the left side of the spine. It is aboat one inch long and forms the end of the duodenum. It is firmly fixed in its place by the musculus suspensorius duodeni, the latter being the name of the fibrous band, containing some plain muscular fibres which descend to the vertical part of the duodenum from the left crus of the diaphragm and the tissues about the coeliac axis. It terminates at this point in the jejunum, forming the flexura duodenojejunalis at a place situated to the left of the second lumbar vertebra.

The Small Intestine.

The small intestine which forms the continuation of the duodenum is composed of the jejunum and ileum. There is really no marked structural difference between the two, and it is therefore hardly possible to determine where one ends and the other begins. As a rule, the upper two-fifths are designated as the jejunum and the lower three-fifths as the ileum. The jejuno-ileum fills the greater part of the abdomen. It occupies the umbilical, hypogastric, iliac, and lumbar regions, and is more or less encircled by the large intestine. The coils formed by the jejunum and ileum are very movable and completely invested by the peritoneum. They are supported and attached to the posterior parietes by the mesentery. The latter extends from the end of the duodenum to the ileocecal junction. The point at which the mesentery is attached above is on a level with the lower border of the pancreas and just to the left of the vertebral bodies. From this point of insertion the mesentery follows an oblique line running downward and to the right, crossing the great vessels and ending in the iliac fossa. The length of the mesentery from the spine

ANATOMY. o

to the intestines varies in different parts of the canal, its average being eight to nine inches. It soon attains its full length, and within one inch of the end of the duodenum is already six inches long. The small intestine hangs on the mesentery in the form of coils, and the folds which the mesentery forms may be compared to those of a fan.

The small intestine including the duodenum has an average length of about twenty feet. The calibre of the small intestine is larger at its upper end and gradually diminishes in size until its entrance into the large boweL Thus at the beginning the jejunum has a circumferential calibre of 17.5 cm., the ileum at its beginning of 11.5 cm., and at its end 9.5 cm. The ileum passes perpendicularly into the ascending part of the colon just above the caecum, its mucosa forming a double valve, the valvula Bauhini. The jejuno-ileum is the most movable part of the intestinal tract. Wherever a free space is left it occupies it. It is therefore most often met with in hernias. During gravidity or when a tumor ur ascites exists in the abdomen the small intestine moves up higher and thus escapes compression.

The small intestine receives its blood supply from the abdominal aorta. The arteria gastroduodenalis, a branch of the arteria hepatica, supplies the upper part of the duodenum; the lower part of the duodenum and the jejunum and ileum are supplied by the arteria mesenterica superior. The latter vessel branches off into a fine net of numerous small vessels which run through the intestinal wall. The end ramifications penetrate the submucosa and here again form a net. From the latter the finest ramifications penetrate the mucosa and form a capillary system of the villi and glands. The venous blood flows partly into the vena gastrica superior, partly into the vena mesenterica superior, and empties itself into the vena porta. The lymphatics

& DISEASES OF THE INTESTINES.

form a continuous series which is divided into two sets, that of the mucous membrane and that of the muscular coat. The lymph vessels of both sets form a copious plexus. They run between the two folds of the mesentery and end in the mesenteric lacteals. They are provided with valves which prevent the current from flowing backward, the direction of which is into the truncus lymphaticus intestinalis and finally into the thoracic duct.

The nerves of the small intestine originate principally from the plexus mesentericus superior or the sympathetic. The duodenum is supplied by the plexus hepaticus, a branch of the plexus cceliacus. The abdominal part of the vagus, namely, the plexus gastricus, anterior and posterior, also supplies the small intestine with nerves. The nerves, which are mostly non-medullary, enter the intestinal wall in connection with the branches of the arteria mesenterica superior and form a subserous net. They then penetrate the long muscular fibres and form between these and the circular muscular fibres ramifications which consist of numerous groups of multipolar cells (plexus mesentericus seu Auerbachii) ; fine branches of nerves arising here supply the muscularis. Others penetrate the circularis, reach the submucosa, and form the submucous nerve plexus, containing small groups of ganglion cells (Meissner's nerve plexus) ; fine ramifications also supply the muscularis mucosae, the muscles of the villi, and end in the remaining part of the mucosa.

Structure of the Small Intestine.

The small intestine is composed of four principal coats : the serous, muscular, submucous, and mucous (Fig. 2). The serous coat is formed by the visceral layer of the peritoneum. The muscular coat consists of an internal circular and an external longitudinal layer (Fig. 3). The former is usually considerably thicker than the latter. They both

Fig. 2.— Longitudinal Cross-section through the "Wall of the Small Intestine (Ileum). Solitary lymph nodules (nodulus lymphaticus solitarius). Intestinal glands (Lieberkuehnii (Toldt). a. The mucous layer; 7). the muscularis mucosa? ; c, the submucous layer ; o\ the muscular layer ; e. the subserosa ; /, the serous layer ; g, intestinal villi : h, intestinal glands (Lieberkuehn) ; i, blood-vessels ; 7c a solitary lymph nodule ; 7, its centre.

consist of bundles of unstriped muscular tissue supported by connective fibres. The submucous coat consists of connective tissue in which numerous blood-vessels and lym-

1 &

Fig. 3.— Longitudinal Cross-section through the Wall of the Duodenum. Brunner's glands (glandulae duodenales) (Toldt). a. The mucous layer ; o. the muscularis mucosae ; c, the submucous layer ; d, the circular muscular layer ; e, the longitudinal muscular layer ; /, intestinal villi ; g, intestinal glands (Lieberkuehn) ; 7?, Brunner's duodenum glands ; i, serous layer.

phatics ramify. The mucous membrane is the most important coat with regard to the function of digestion. It

DISEASES OF THE INTESTINES.

consists of a very thin muscular layer (muscularis mucosae) containing circular and longitudinal fibres, the tunica propria of the mucosa, a tissue made up principally

of reticular connective tissue with numerous leucocytes, glands, and the epithelial covering.

The mucous membrane of the small intestine is of a grayish-red color and has a velvety appearance. It possesses certain large folds of valvular flaps (valvulse conniventes Kerkringi) (Fig. 4). These are permanent crescentic folds of mucous membrane set transversely to the long axis of the intestine. Each one extends from one-half to two-thirds of the distance of the lumen. The largest are more than two inches long and about one-third of an inch wide. They begin somewhat below the pylorus, are very large just below the entrance of the bile duct, remain conspicuous until the middle of the jejunum is reached, then become smaller and gradually disappear at the lower part of the ileum. They serve to increase the surface of the mucous membrane.

The microscopical anatomy of the mucous membrane reveals the following : The entire inner surface of the small intestine is composed of villi, certain papilliform processes, .and glands ; an epithelial layer containing columnar epi-

Fig. 4.— Jejunum Partly Opened (Toldt). a, Serosa ; 6, mucosa ; c, circular folds of Kerkring.

thelial cells with a striated border, and some goblet cells cover the entire surface. The villi are formed principally by elevations of the tunica propria of the mucous membrane (Fig. 5). They are about 0.5 to 0.7 mm. in height and about 0.1 to 0.2 mm. wide and number almost ten millions. Each villus possesses a centrally located space for chyle which is covered with endothelial cells and connected with the lymphatics of the intestinal mucosa. Each villus contains a perfect arrangement of blood-vessels and muscular fibres which originate in the muscularis mucosa?. When rilling up with blood each villus expands, while under the contraction of its muscle it shrinks. Thus it is enabled to perform the function of suction and pumping. The villi form the main organ for m the the absorption small intestine.

Around the villi lie their glands. First, there are tubular glands (of Lieberkiihn), and, secondly, acinous glands of Brunner. The former are similar in structure to the tubular glands in the stomach. They cover almost the entire surface

of the whole small and large intestine. Each glandular tubule is about 0.3 to 0.4 mm. long and opens without forming any ramifications. They number over forty millions and form the principal organ of intestinal secretion. Brunner' s glands are confined to the duodenum. They are most abundant at the commencement of this portion of the intestine, diminishing gradually as the duodenum

Fig. 5. — Mucous Membrane of the Ileum with a Solitary Lymph Nodule (Toldt). a. Intestinal glands (Lieberkuehn) ; o, intestinal villi ; c, a solitary lymph nodule.

DISEASES OP THE INTESTINES.

advances. They are situated beneath the mucous membrane and embedded in the submucous tissue. Each gland is a branched and convoluted tube lined with columnar epithelium. In structure they are very similar to the pyloric glands of the stomach, but are more branched and convoluted, and their ducts are longer. The duct of

each gland passes through the muscularis mucosae and opens on the surface of the mucous membrane.

Solitary follicles or glands are found scattered throughout the mucous membrane of the small intestine. They are most numerous in the lower part of the ileum.

Each one has a diameter of from 3 to 6 mm. The structure of the solitary follicle is similar to that of the lymph nodes and consists of a dense retiform tissue packed with lymph corpuscles and permeated by fine capillaries. There are no ducts. The interspaces of the retiform tissue are continuous with larger lymph spaces at the base of the gland, by which they communicate with the lacteal system. The base of the nodules is in the submucous tissue. It penetrates the muscularis mucosae and enters the mucous membrane forming a slight projection of its epithelial layer. The solitary follicles are the breeding place of the lymph cells. They

Fig. 6.— Ileum Partly Opened (Toldt). a. Solitary lymph nodules; b, serosa; c, mucosa.

ANATOMY.

are met with in two conditions, namely, either scattered singly, in which case they are termed glandulse solitaries (Fig. 6), or aggregated in groups varying from one to three

IpHraigisig

Fig. 7.— Peyer's Patch (Noduli Lymphatici Aggregati) in the Ileum (Toldt). a, Peyer's patch ; b, solitary lymph nodules.

inches in length and about one-half inch in width. The surface of the solitary follicles is free from villi. Chiefly of an oval form, their long axis is parallel with that of the intestine. In this state they are called glandulse agminatae or Peyer's patches or plaques (Fig. 7). They are almost always placed opposite the attachment of the mesentery. Peyer's patches number about twenty to twenty-eight. In some cases they are already found in the jejunum, but they are most prevalent in the ileum.

The Large Intestine or Large Bowel (Intestinum Crassum)..

The large intestine extends from the termination of theileum to the anus. It is about five to six feet in length. Its calibre decreases from beginning to end except at the ampulla of the rectum where it is larger. It measures 28.5 cm. in circumference at the iunction of colon and cse-

DISEASES OF THE INTESTINES.

cum, 20.5 cm. at the end of the ascending portion, 14.5 cm. in the descending portion. The large intestine is divided into the caecum, colon, and rectum. With the exception

of the rectum it possesses three taeniae, these being groups of nonstriated muscular fibres running lengthwise with the lumen of the intestine.

Between the taeniae the walls are somewhat sacculated. The circular muscular fibres are also accumulated in spots, leaving short intervals between each other, thus forming c o n - strictions and expansions (haustra coli) across the intestine (Fig. 8). The large bowel is further characterized by appendices epiploicae, external pouches, formed by the peritoneal covering containing fat. The caecum is the head of the colon or that part of the large bowel situated below the mouth of the ileum (Fig. 9). It lies in the right iliac fossa and is

6 f

Tig. 8.— The Large Bowel Partly Opened along the Mesentery (Toldt). a, Free taenia; ft, taenia mesocolica; c, appendices epiploicae ; d, the mucosa ; e, the semilunar folds of the colon ; /, the mesocolon.

ANATOMY.

ia completely covered by the peritoneum. In the filled condition it. touches the anterior abdominal wall. Starting from the inner and back portion of the csecum lies the processus vermiformis or appendix, forming a narrow, somewhat bent, blind-ending tube. The appendix is movable and has its own a

mesentery (mes- /:

enteriolum).

Its length varies between 2 and 20 cm. and its width between 0.5 and 1 cm.

The appendix opens into the csecum (ostium processus vermiformis), occasionally forming a crescentic fold (v a 1 v u 1 a processus vermiformis) . I n man it constitutes an entirely functionless organ which occasionally gives rise to manifold

ailments. The appendix has no fixed position. J. I>. Bryant 1 found it most often "inward," then "behind the caecum," "downward and inward," "into the true pelvis." ' J. D. Bryant : Annals of Surgery, February, 1893, p. 164.

Fig. 9.— Section of the Caecum and Ileum, showing the Entrance of the Latter into the Caecum (Toldt). a, The semilunar folds of the colon ; b, c, the ileocaecal valves (b, the upper, and c, the lower one) ; d, the end portion of the ileum ; c, the posterior ileocaecal valve ; /, the appendicular valve ; y, the appendix.

Without distinct demarcation the caecum merges into the ascending colon. It passes vertically above the crest of the ileum and runs along the posterior abdominal muscles and the lower part of the right kidney. At this point just in front of the kidney and immediately beneath the liver the colon bends toward the left of the flexura coli dextra. The ascending colon is posteriorly adherent through connective tissue with the jjarts just mentioned, while the peritoneum covers only its anterior and partly also its lateral surfaces. In close proximity to its median wall lies the ascending part of the duodenum. Beginning at the flexura coli dextra the colon runs across the abdominal cavity from right to left (transverse colon), forming the longest segment of the large intestine. It passes from the hepatic flexure in the right hypochondrium transversely and slightly upward from right to left along the anterior abdominal wall to the splenic flexure in the left hypochondrium. This part of the colon is the most movable. It has a very long mesentery, called the transverse mesocolon. The usual position of the transverse colon corresponds to a line separating the umbilical and epigastric regions. It is in relation by its upper surface with the lower part of the liver and gall bladder, the greater curvature of the stomach and the lower end of the spleen; by its under surface with the small intestine ; by its anterior surface with the great omentum and abdominal wall; by its posterior surface with the transverse mesocolon ; on the right side with the second part of the duodenum, and on the left besides the latter with some convolutions of the small intestine.

The transverse colon does not form a straight line connecting the right and left flexures, but is about twice as long as this line and therefore forms several curves. In the left hypochondrium especially, there is an S-shaped coil. The latter fills out the free space in the left hypochondrium which is left by the stomach in its various states of fulness. Beginning at the flexura coli sinistra the descending colon runs downward in front of the left kidney and the quadratus lumborum and iliac muscles until it reaches the left iliac fossa. The descending colon runs just in the opposite direction to the ascending colon, and like this is only partly covered bj r the peritoneum. The descending colon passes into the sigmoid colon or flexure (S Romanum), commencing above the iliac crest and ending below in the rectum at the brim of the true pelvis opposite the left sacro-iliac articulation. It is generally described as an S-shaped curve having an upper colic rim turned toward Poupart's ligament and the lower rectal rim, hanging down into the true pelvis. It has a complete peritoneal covering or mesentery. This part of the bowel is very movable, and its calibre is the narrowest of that of the large bowel. The sigmoid flexure continues into the rectum, forming the terminal portion cf the intestinal tube. It runs, coming from the left, in front of the os sacrum down to the bottom of the small pelvis. Only the upper half of the rectum is invested completely with peritoneum (mesorectum) and is attached to the sacral vertebra. The lower half passes between the organs occupying the pelvic floor, being adherent to them by connective tissue. It now runs posteriorly along the os coccyx and terminates in the anus. This part has an incomplete peritoneal covering (plica Douglasii) lying anteriorly and turning backward in order to ascend either over the vagina or the bladder (excavatio recto-uterina, excavatio rectovesicalis). Below this point the rectum has very little mobility as it is covered all around by connective tissue. The entire rectum is about 18 to 22 cm. long. Its calibre varies. It is widest at the apex of the prostate, forming the ampulla of the rectum.

The longitudinal muscular fibres of the rectum are not arranged in taeniae as in the colon, but pass all around the lumen. The circular muscular fibres become more dense from above downward and increase to such a degree at the anal opening that they here form a thick ring (musculus sphincter ani internus). A short distance above this muscle there is also an accumulation of circular muscular fibres (musculus sphincter ani tertius). At the anus the walls of the rectum are connected with striated muscular fibres (sphincter ani externus and levator ani), which are both of importance in the act of defecation.

The colon is supplied by the three arteriae colicae, branches of the arteria mesenterica superior and arteria mesenterica inferior. The arteria colica sinistra originates from the arteria mesenterica inferior, while the arteria colica media and superior are tributaries of the arteria mesenterica superior. The veins accompany the artery and empty partly into the vena mesenterica superior, partly into the vena mesenterica inferior. The lymphatics of the colon are numerous and lie below the glands and all through the submucosa. The plexus mesentericus superior, a branch of the plexus cceliacus, provides the nervous supply of the caecum, ascending colon, and the right half of the transverse colon. The plexus mesentericus inferior, a branch of the plexus aorticus abdominalis, supplies the left half of the transverse colon, the descending colon, and the sigmoid flexure.