References

Connell TR, Stephens DH, Carlson HC, et al Upper abdominal abscess A continuing and deadly problem. AJR 1980 134 759-765. 2. Wang SMS, Wilson SE Subphrenic abscess The new epidemiology. Arch Surg 1977 112 934-936. 3. Wetterfors J Subphrenic abscess A clinical study of 101 cases. Acta Chir Scand 1959 117 388-408. 4. Samuel E, Duncan JG, Philip T, et al Radiology of the postoperative abdomen. Clin Radiol 1963 14 133-148. 5. Annotation Subphrenic abscess A changing pattern. Lancet 1970 2 301. 6....

The Gastrocolic Ligament and the Omentum

The gastrocolic ligament attaches the greater curvature of the stomach to the anterior surface of the transverse colon and extends anteriorly as an apron to become the omentum covering the colon and small bowel in the peritoneal cavity. The gastrocolic ligament is in continuity with the gastrosplenic ligament on the left side of the abdomen, and it is fused with the transverse meso-colon on the right side of the abdomen as it is inserted and attached to the retroperitoneum behind the pylorus...

The Gastrosplenic Ligament

The gastrosplenic ligament extends from the posterolateral wall of the fundus and the greater curvature of the stomach to the splenic hilum. It forms the lateral boundary of the lesser sac. The vascular landmarks of the gas-trosplenic ligament are the short gastric artery and vein at the fundus and the segment of the left gastroepiploic artery and vein branching from the splenic artery and vein at the hilum of the spleen along the body of the stomach. Table 6-1. Peritoneal Ligaments Derived...

The Gastrohepatic and Hepatoduodenal Ligament

The gastrohepatic ligament suspends the cardia and the lesser curvature of the stomach from the inferior surface of the liver. It inserts deep into the fissure of the liga-mentum venosum anterior to the caudate lobe of the liver. It separates the lesser sac from the perihepatic space posterior to the lateral segment of the left lobe and forms the anterior boundary of the lesser sac. Caudally, the free edge of the gastrohepatic ligament becomes the hepa-toduodenal ligament. The vascular...

A J

Tubo Ovarian With Paracolic Gutter

Metastatic seeding in the sigmoid mesocolon from gastric carcinoma. Circumferential invasion has occurred but the predominant effect can be identified on the superior contour of the sigmoid colon. Fig. 4-140. Metastatic seeding in the sigmoid mesocolon from pancreatic carcinoma. Double-contrast study demonstrates that seeded deposits accompanied by desmoplastic reaction result in mass compression with tethered mucosal folds on the superior border of the sigmoid colon (arrows). At...

Embolic Metastases

Malignancies shed as many as 4 million cells per gram of tumor tissue into the bloodstream per day. Of these, greater than 90 are cleared rapidly from the circulation.231,232 Despite this metastatic inefficiency, the abdominal organs and bowel are a common site of he-matogenous metastases from both intraabdominal and The most common primary neoplasms that embolize to bowel include melanoma and tumors of the breast and lung. The presenting picture is usually one of incomplete obstruction or...

Retroduodenal and Intramural Duodenal Hematoma

Blunt trauma or acute deceleration may also cause rupture of the small blood vessels behind the fixed second portion of the duodenum. The hematoma resides within the right anterior pararenal space. It results in a characteristic spiculation of the mucosal folds of the pos terior margin of the descending duodenum and may displace that structure anteriorly (Fig. 8-58). Confirmation of its presence, precise localization, and extent is readily shown by CT, which is also useful in follow-up to...

Seeded Sites

Morrison Pouch Right Paracolic Gutter

Stasis or pooling of ascitic fluid favors the processes of deposition, fixation, and growth of seeded malignant cells. The seeded deposits coalesce and are then fixed to Fig. 4 105. (a) Posterior peritoneal reflections and intraabdominal spaces. TrM transverse mesocolon PL phrenicocolic ligament SBM small bowel mesentery AC attachment of ascending colon DC attachment of descending colon SM sigmoid mesocolon R rectum B urinary bladder RIS right infracolic space LIS left infracolic space RPG...

Choledochal Cyst

Air Biliary Tree

Cystic disease of the liver may encompass many findings, including intra- and extrahepatic (renal and pancreatic) cysts and hepatic fibrosis. Choledochal cysts are a separate entity, although they may also exhibit a wide range of radiographic findings. Proposals regarding their cause include intrauterine bile duct obstruction, atypical junction of the pancreatic and common bile ducts (Fig. 232), an anomalous course of the primitive common bile duct through the duodenal wall, a malformed common...

Hepatic Notch

Hepatic Edge Sign

The ligamentum teres notch is an indentation in the inferior hepatic margin situated between the lateral and medial segments of the left lobe. Consequently, it can be visualized as an inverted V-shaped lucency in the right upper quadrant, with its superior borders delimiting the liver edge5,16 (Fig. 7-18). The ligamentum teres, if outlined with air, may be seen directed toward the notch. A lucent collection in the left lower quadrant (arrow) represents free air between a bowel loop and the...

The Right Side

On the right side, the descending duodenum may be abnormally positioned posteriorly. Normally, the second portion of the duodenum descends immediately anterior to the medial half of the right kidney. In the right lateral projection during an upper gastrointestinal series, the descending duodenum projects anterior to the lumbar spine. With congenital absence or failure of ascent of the right kidney, the descending duodenum may occupy the area of the renal bed and project well over the lumbar...

The Hepatic and Splenic Angles

Fever Unknown Origin

The hepatic and splenic angles, the posterior and inferior contours of these intraperitoneal organs, are out lined normally by the contrast provided by the subjacent extraperitoneal fat.65 Figure 8-39 shows that the lateral aspects of the angles are adjacent to the lateral extension of the posterior pararenal fat, while the medial aspects are related to the anterior pararenal and perirenal fat. Loss of their visualization, however, is a nonlocalizing abnormality. Either intraperitoneal...

Inframesocolic Extension of Neoplasm of Third Duodenum

The third portion of the duodenum lies retroperito-neally below the root of the transverse mesocolon. Extension of a mass arising in this structure is then revealed on barium enema examination by a characteristic elevation of the proximal transverse colon (Fig. 10-33a). While this type of displacement may occur secondary to such conditions as mesenteric cysts or primary ret- Fig. 10-33. Leiomyosarcoma of third portion of the duodenum with large extramural component. (a) There is gross elevation...

Intersigmoid Hernias

The intersigmoid fossa is a peritoneal pouch formed between the two loops of the sigmoid colon and its mesentery. This pocket is found in 65 of cadavers and serves as a potential site for an intersigmoid hernia.9'16'18 This is usually a reducible hernia containing a few small bowel loops. Incarceration is uncommon. The radiologic diagnosis of intersigmoid hernia is best made by retrograde filling of the small intestine during barium enema examination. Figure 16-37 shows the encapsulated ileal...

The Subperitoneal Space Normal and Pathologic Anatomy

Berne, M.D. Morton A. Meyers, M.D. Conventional distinction between intraperitoneal and extraperitoneal sites is often helpful in differential diagnostic considerations.1'2 Yet it should be understood that the abdomen and pelvis constitute an anatomic continuum that is punctuated by the mesenteries, ligaments, and fasciae, which may either confine pathology or actually provide an avenue for disease spread. It is essential to recognize the anatomic continuity of...

Anatomic Considerations

Peritoneal Reflections

Virtually all of the pancreas is an extraperitoneal organ. However, a nonperitonealized bare area results from the reflections of the posterior parietal peritoneum to form the two leaves of the transverse mesocolon.7 This extends across the lower border of the organ anteriorly (Fig. 11-1). On the right, the transverse mesocolon begins at the point where the anterior hepatic flexure of the colon immediately crosses ventral to the second portion of the duodenum. The bare area then extends as a...

Perirenal Gas Producing Infection

Where Iliac Crest Bladder

The radiologic features of a perirenal space gas-producing infection are distinctive. Its recognition is related directly to an understanding of the characteristic appearance of the acutely distended cone of renal fascia and the preferential spread through the rich perirenal fat dorsal to the kidney. The gas may encircle the kidney or present as a mottled collection of radiolucencies within the shadows of the perirenal fat. Figure 8 124 illustrates the typical distribution in a diabetic female....

Contents

Foreword to the First Edition by R.H. Foreword to the First Edition by L.M. 1 General Considerations Dynamics of Image Normal Anatomic Relationships and Dynamic Principles of Pathways of Spread and Localization of Disease 1 2 Clinical Embryology of the Abdomen Normal and Pathologic Bruce R. Javors, M.D., Hiromu Mori, M.D., Morton A. Meyers, M.D., and Ronald H. Wachsberg, M.D. Early Development of the Embryologic Rotation and Fixation of Ectopic and Accessory Hepatic Duct Aneurysmal Dilation of...

Portal Venous System

Cholelithiasis

Of the three major venous systems traversing the upper fetal abdomen (i.e., the cardinal, vitelline, and umbilical systems), the latter two are integral to the development of the hepatic vasculature. The right vitelline and left umbilical veins persist, whereas their respective contralateral counterparts are short-lived. The right vitelline vein forms a plexus surrounding the duodenum and extending to the septum transversum, where it interacts with the developing liver cords to form the hepatic...

Lesser Sac Abscesses

Anatomically, Morison's pouch communicates with the lesser sac via the epiploic foramen. Noninfected intra-peritoneal fluid originating within the greater peritoneal cavity may thus readily gain entrance to the lesser sac (Figs. 3-68 through 3-71). However, this slitlike connection is easily sealed off by adhesions, so the lesser sac is not usually contaminated in generalized peritonitis unless the primary infection arises in the walls of the lesser sac itself. Abscesses here are therefore...

Radiologic and Arteriographic Features

Mesenteric Margin Small Intestine

The preoperative diagnosis of paraduodenal hernia can be established only by radiologic evaluation. Studies are best performed during a symptomatic period. Examination in intervals between recurrent internal herniation may be negative or may demonstrate mild degrees of dilatation, stasis, and perhaps edematous mucosal folds that may be falsely attributed solely to adhesions. Diligent serial filming is essential to diagnosis. In patients with a small left paraduodenal hernia (Figs. 16-6 through...

Nodal Metastasis

Pancreaticoduodenal Lymph Node

Lymph node metastases are common in pancreatic tumors because of rich lymphatic networks around the pancreas. They are found in 40-75 of patients with tumors larger than 2 cm on pathologic examinations.4 The majority of lymph node metastases are found at the peripancreatic nodal group, including the anterior and posterior peripancreatic nodes, pancreaticoduodenal lymph nodes, pyloric nodes (Fig. 12-13), and inferior Fig. 12 12. Ductal adenocarcinoma of head of pancreas. Tumor (T) involves the...

Hemorrhage

Posterior Pararenal Space Collection

Retroperitoneal bleeding accompanying renal trauma or fractures of the spine or posterior ribs may be identified as residing largely within this space (Fig. 8-190). Many cases of extraperitoneal hemorrhage due to bleeding dyscrasias (Fig. 8-191) or overanticoagulation (Fig. 8-192) can be identified precisely as developing within the posterior pararenal compartment. The distinctive complex of findings is evaluated easily, and the Fig. 8 188. (a) Postmortem injection into the left posterior...

Seeded Metastases on the Greater Omentum

Intrahepatic Lesion

A characteristic feature of the greater omentum, projecting as the fatty apron of the abdomen, is its associated lymphoid tissue, known as milky spots. These are composed of numerous macrophage and lymphocyte aggregations surrounding a capillary convolution.167,168 The mesothelial cells overlying these areas are loosely connected and lack basement membranes.169171 They act as open lymphatic lacunae that absorb peritoneal fluid and thereby bring tumor cells in large quantity to this struc- ture....

Diffuse Extraperitoneal

Position Diaphragm When Erect

Radiologic localization of diffuse extraperitoneal gas to a specific compartment is greatly advanced by anatomic knowledge gained from careful study of body sections, postmortem injections, and retroperitoneal pneumog-raphy.9 Fascial boundaries and tissue planes direct the spread and localization of extraperitoneal gas, depending on its source. In presacral pneumography, if the needle is inserted in the midline behind the rectum, the gas ordinarily rises symmetrically up both sides.13 While the...

Vascular Anatomy

Waveform For Right Anterior Portal Vein

The pancreas receives blood supply from multiple branches of the celiac axis and the SMA.5-8 The head of the pancreas is supplied by a network of arteries that originates from three major arteries (Fig. 12-1). The gastroduodenal artery (GDA) descends from the common hepatic artery (CHA) in the retropyloric space between the pylorus and the cranial portion of the head of the pancreas. Proximally, it gives off a branch posteriorly that runs along the posterior lateral surface of the pancreatic...

Hepatic Flexure

With spread of liberated enzymes from the head of the pancreas into the right anterior pararenal space across the beginning of the transverse mesocolon, the hepatic flexure may show localized or diffuse inflammatory changes (Fig. 11-6). Occasionally, the cut-off process of a stricture resulting from pericolic fat necrosis may closely simulate an annular carcinoma2,10 (Fig. 11-7). In 1956, Price11 coined the term colon cut-off sign in acute pancreatitis for isolated gaseous distention of the...

Pneumoscrotum

Left 12th Rib

Rarely, free air can extend into the scrotum through the open processus vaginalis (Fig. 7-31). This unusual sign of large pneumoperitoneum occurs only in males. It is anatomically interesting but never crucial for the diagnosis. Fig. 7 28. Ligamentum teres fissure sign with less than 1 mL of air seen on supine film. (a) On this plain radiograph, a tiny lucency above the 12th rib medially (arrowhead) represents free air trapped in the fissure. Anterior superior bubbles are also seen laterally....

Anatomic Consideration

Left Inferior Phrenic Vein

The large intestine consists of the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. The ascending colon, descending colon, and rectum are considered extraperitoneal organs because the ascending and descending colon lie in the anterior pararenal space and are covered by a single layer of the posterior peritoneum, while the rectum is surrounded by extraperitoneal perirectal fat in the pelvis. The transverse colon and sigmoid colon are suspended in the...

Spread of Infection via Perihepatic Ligaments

Gastrocolic Gutter

Intraabdominal infections and inflammatory processes may spread and localize not only within the recesses of the peritoneal cavity but along the peritoneal ligaments and mesenteries as well. I have previously recognized that these structures may provide the avenues of spread by direct invasion by malignancies. Mori and colleagues have reported the exophytic spread of he-patobiliary disease along the perihepatic ligaments,74 and Arenas et al.75 have further detailed inflammatory and infectious...

Ptosis and Rotation

Ptotic Kidney

Ptotic descent of the kidney is frequently accompanied by rotation about its vertical axis. The condition is more common on the right where its effects on the bowel Fig. 9 21. Displacement of the left colon by left renal cyst. (a and b) The anatomic splenic flexure (SF) is maintained, but there is lateral and anterior displacement of the descending limb of the distal transverse colon (arrows). The mass enlargement of the lower pole of the kidney is identifiable (large arrows). (Reproduced from...

Local Organ Invasion

Splenic Tumor

Pancreatic ductal adenocarcinoma has a propensity to invade adjacent organs and structures surrounding the pancreas, depending on the site of the primary tumor. The tumors in the tail and body of the pancreas often present at an advanced stage because of the lack of symp toms (Fig. 12-4). The tumors may involve the spleen, stomach, and the splenic flexure of the colon, and not infrequently, they invade the surrounding retroperitoneal organs such as the left adrenal gland, the upper pole of the...

The Right Kidney

Peritoneal Reflection Colon

The right kidney is in intimate relationship to two segments of the gastrointestinal tract the descending duodenum and the hepatic flexure of the colon. Figures 91 and 9-2 illustrate these relationships and the reflections of the posterior parietal peritoneum in the right flank. Virtually all of the right kidney is invested anteriorly by peritoneum except at two sites constituting its bare areas 1. Medially, the second portion of the duodenum de scends immediately in front of the right kidney....

Ligamentum Teres

The ligamentum teres is a fibrous cord representing an obliterated left umbilical vein.21 Lying in the free edge of the triangular falciform ligament, the ligamentum teres ascends from the umbilicus to the ligamentum teres notch at the inferior border of the liver (Figs. 7-1 and 7-9). It then enters the liver, traverses the fissure for the ligamentum teres, and terminates by joining the left portal vein at the left extremity of the porta hepatis opposite the attachment of the ligamentum...

Bowel Loops

Antimesenteric Border Bowel

It is necessary to recognize the axis of the root of the mesentery and the undulating, changeable nature of the small bowel loops to understand the basis for the radio-logic identification of their mesenteric and antimesen-teric borders.1 Figure 14-9 illustrates certain constant geometric properties of the mesentery. The base of the mesentery, from which the jejunum and ileum are suspended, is essentially a series of alternating convexities and concavities connected by intervening limbs. Any...

Extraperitoneal Gas of Supradiaphragmatic Origin

Anterior Left Subphrenic

Gas arising above the diaphragm may pass down the mediastinum through the diaphragmatic hiati and directly into the posterior pararenal space. If the gas gains entrance to structures of the chest wall, its extension to the extraperitoneal tissues of the abdomen may pursue a characteristic course. The endothoracic fascia of the chest is continuous with the transversalis fascia of Fig. 8 213. Extraperitoneal gas in all three spaces secondary to rectal perforation from colonoscopic polypectomy....

Compartmentalization of the Anterior Pararenal Space

Michiel A.M. Feldberg, M.D. The space based on fascial boundaries, enclosed by the posterior parietal peritoneum anteriorly, the anterior renal fascia posteriorly, and the lateroconal fascia laterally, has been termed the anterior pararenal space by Meyers et al.12 It contains the extraperitoneal alimentary structures, namely the pancreas, duodenum, and ascending and descending colon. Because the spread of fluids, inflammation, and gas does not always conform to the...

The Transverse Mesocolon

Mesocolon Transverse

Anatomic dissections and injection experiments have documented that the mesenteric plane of the transverse mesocolon extends preferentially downward along the TM-TL haustra toward the TO-TL row5 (Fig. 15-27). This constitutes the inferior border of the transverse colon. Pancreatic lesions, by extending along the leaves of the transverse mesocolon, may then be revealed by their characteristic effects on the inferior haustral row. In severe pancreatitis, extravasated enzymes typically flatten the...

Abnormal Imaging Features

Hepatoduodenal Ligament

The continuity of the subperitoneal space and its interconnections is vividly demonstrated by CT in Figures 13-9 and 13-10. Subperitoneal gas is seen diffusing Fig. 13 9. Gas originating in the mediastinum diffusing inferiorly via the subperitoneal space through the abdomen and pelvis. (a) CT scan at lower thorax. Pneumomediastinum is seen anteriorly (arrow 1) (b) Scan through upper abdomen at esophagogastric junction. E esophagus Ao aorta. Note gas (arrow 2) as it courses through the...

U ao J

Paracolic Ligament

Sagittal section through the left lobe of the liver. The smaller left lobe (LL) of the liver lies anterior to the stomach (S), including both its upper fundic and distal body portions. Ao aorta. Fig. 3 14. Peritoneal attachments and recesses of the left upper quadrant. (a) Diagram of horizontal section. The intraperitoneal spaces around the left lobe of the liver and the spleen are freely continuous (gray area). The perisplenic space is bounded by the splenorenal and gastrosplenic...

Dorsal Mesentery Derivatives

Subperitoneal

The dorsal mesogastrium gives rise to a series of ligaments interconnecting the organs in the left upper abdomen the gastrosplenic, splenorenal, and gastrocolic ligaments and the greater omentum. This network of ligaments in the left upper quadrant establishes local continuity between the stomach, spleen, pancreas, left kidney, and transverse colon and global continuity with the entire abdomen as extensions of the subperitoneal space.1,3,5,6,18-20 Fig. 13 7. Anatomic drawing of the...

Duodenocolic Fistulas

Proximal Transverse Colon

Although most duodenocolic fistulas result from an infiltrating adenocarcinoma of the hepatic flexure,11 the communication may be established by ulcerative or inflammatory disease.1214 Granulomatous colitis is being increasingly recognized as an underlying cause.13,14 With the right-sided colonic involvement of this transmural inflammatory and ulcerating condition, fistulization may develop between the hepatic flexure particularly or the transverse colon and the duodenum (Figs. 10-14 through...

Diverticulosis of the Small Intestine

Diverticulosis Small Intestine

Acquired diverticula of the small bowel are usually multiple and are practically limited to the upper part of the jejunum.3 Examination of a specimen (Fig. 14-14a) documents that the diverticula do not arise randomly from the circumference of the small intestine but are strikingly situated at or immediately alongside the mes- Table 14 1 Pathologic localization Sole or predominant border of small bowel involved Diseases Mesenteric Antimesenteric Diseases Mesenteric Antimesenteric Fig. 14 14....

The Left Kidney

Image Anterior Peritoneal Reflection

The relationships of the left kidney to the bowel are most intimate to the distal transverse and proximal descending colon. Figure 9-3 illustrates these relationships and the complex peritoneal reflections in the left flank. The reflections of the transverse mesocolon cross the left kidney anteriorly along a narrow bare area at thejunc-tion of its middle and lower thirds to continue with the peritoneal reflections over the descending colon. At the junction of the transverse and the descending...

Sigmoid Perforation

Diverticulitis Sigmoid

The sigmoid colon lies below the limits of the cone of renal fascia where it is in anatomic continuity with both the anterior and posterior pararenal spaces (Fig. 8-215). Gas from a sigmoid perforation may therefore enter either or both compartments. Studies by Meyers et al.269,270 have confirmed that only one of the four rows of colonic diverticula faces the peritoneal cavity and that fully 75 of sigmoid di-verticula are related to the extraperitoneal tissues. Ex-traperitoneal gas associated...

Mixed Collections

Fascial Spaces For Molars

As a rule, large pelvic collections occupy several spaces with multiple possibilities involvement of several ex traperitoneal spaces or association of intraperitoneal and extraperitoneal collections (Figs. 8-234 through 8-236). In patients with large amounts of fluid in the infrarenal extraperitoneal space, extension into the pelvic extra-peritoneal space is not rare. The dorsal extension medial to the iliac vessels and or a more medial extension into the prevesical space are the most common...

Seeded Perihepatic and Subdiaphragmatic Metastases

Ruptured Cyst Ovaries

Conventional radiologic studies have disclosed the intraperitoneal spread of seeded metastases to the supra-mesocolic compartment only on occasion. This pathway of spread is illustrated graphically in Figure 4-148 in an instance of a spilled ovarian dermoid cyst.110 The avenue and characteristic sites of implantation are clearly mapped out in the patient studied by CT in Figure 4149. Seeded deposits in both Morison's pouch and the right subphrenic space are therefore not uncommon (Fig. 4-150)....

Left Subphrenic Abscesses

Abscesses in the left subphrenic space may result from perforated anterior ulcers of the stomach or duodenal bulb, but they are seen particularly as complications of gastric or colonic surgery and of splenectomy. The most consistent aspect of flow of fluid arising in the left upper quadrant is that it is preferentially directed upward to the subphrenic area, where an abscess typically coalesces56 (Figs. 3-86 through 3-88). This is a function of the negative intraabdominal pressure beneath the...

Masses Within the Mesocolic Leaves

Antecolic Loop Gastrojejunostomy

Pathologic alteration in the contour of the duodenum by a localized abnormality arising in the origin of the reflections of the transverse mesocolon is shown in Figure 10-10. The bare area is widest at this site so that symmetric growths developing within the leaves may impress upon the duodenum over a considerable length. The typical points of pressure then are at the immediate infraampullary and the genu locations. Fig. 10-8. The transverse mesocolon (arrows) is outlined by the limitation of...

Sources of Effusions

Renal Fascia Radiology

The overwhelming majority of perirenal abscesses are secondary to a renal infection. The underlying condition is most often pyelonephritis, tuberculosis, or carbuncle. Perforation of the renal capsule then leads to contamination of the perirenal space. Fig. 8-117. Coronal anatomic section. The cone of renal fascia (arrows) envelops the adrenal gland, kidney (K), and perirenal fat. Medially it blends with the fascia of the psoas muscle (PM). The perirenal fat is particularly abundant in...

Retroanastomotic Hernias

Billroth Series Gastroduodenal

Retroanastomotic hernias occur usually in patients who have undergone partial gastrectomy and gastrojejunostomy, particularly of the antecolic variety.11,86 The superior border of the hernial ring is formed by the transverse mesocolon, the inferior border by the ligament of Treitz, and the anterior aspect by the gastrojejunostomy together with the afferent limb of the jejunum11 (Fig. 16-51). The herniated loop is usually the efferentjejunal segment or, less commonly, an excessively long...

Internal Hernias Through the Foramen of Winslow

Radiology Foramen Winslow Images

The greater peritoneal cavity communicates with the omental bursa (lesser peritoneal sac) through the epiploic foramen of Winslow. This potential opening is situated beneath the free edge of the lesser omentum, cephalad to the duodenal bulb and deep to the liver, and usually admits one and occasionally two fingers. In life, its anterior and posterior boundaries are usually in contact. The foramen may open to some extent when the trunk is flexed, as in the sitting position. The omental bursa is...

Metastatic Melanoma

Melanoma Bowel Metastases Radiology

Metastatic melanoma is by far the most common of these tumors to be encountered clinically, and it may be taken as a particular prototype. The hematogenous deposition is usually in the submucosal layer where it may be seen early as small mural nodules, and growth typically results in polypoid masses with a bulky extension into the lumen. ' ' There is no significant desmo-plastic response. Central ulceration is especially common as the metastasis outgrows its blood supply. In smaller lesions,...

Anatomy of the Pancreas

Inferior Pancreaticoduodenal Artery

The pancreas lies transversely along its long axis in the anterior pararenal space of the retroperitoneum. 5,6 The head of the pancreas lies within the C-loop of the second portion of the duodenum. The lateral surface of the head is against the serosa of the duodenum. The posterior surface of the head is separated from the inferior vena cava by only retroperitoneal fat and on occasion small posterior peripancreatic nodes. Medially, the head of the pancreas is closely related to the superior...

Direct Intestinal Effects Unique to Renal Ectopia

Bowel And Spleen

Ectopic kidneys may be located in the true pelvis (63 ), in the iliac fossa or opposite the crest of the ilium (8 ), or in the abdomen below the level of the second or third lumbar vertebra and above the crest of the ilium (29 ).24 In cases of ectopic kidney in the true pelvis, there is usually no definite pressure effect upon the sigmoid colon, presumably because the kidney within the sacral hollow does not come into relationship with the anteriorly directed sigmoid loops.16 However, renal...

Summary

Sigmoid Diverticulosis

Table 15-1 summarizes the basic features that enable identification of the specific haustral rows and the most Fig. 15-67. Diverticular involvement by Crohn's disease. Noncaseating granulomas (arrows) involve the mucosa of two sigmoid diverticula. (Original magnification, X 8.) (Reproduced from Meyers et al.46) Fig. 15-67. Diverticular involvement by Crohn's disease. Noncaseating granulomas (arrows) involve the mucosa of two sigmoid diverticula. (Original magnification, X 8.) (Reproduced from...

Undulating Changeable Nature of Coils of Bowel Loops

The Root Small Bowel Mesentery

A fan-shaped supporting ligament such as the mesentery, with an attachment of only 6 in. and an average length of 8-9 in., must suspend 20-22 ft of small bowel. This remarkable feat is accomplished by the unique plication or frilling of its intestinal border. The mesentery extends from its root in a series of fanlike ruffles. This geometric arrangement provides an unusually long border to suspend the jejunum and ileum. It is precisely this feature that contributes to the characteristic...

Embryologic Considerations

Diagrams Falciform Ligament

Knowledge of the development of the subperitoneal space is a prerequisite to recognizing pathologic conditions and understanding the pathogenesis of direct spread.8-11 The conceptualization of the abdomen and pelvis as one space, the subperitoneal space, and its continuity with the thorax requires the reexamination of standard embryology from a holistic perspective.1'4'5'7'12 The primitive coelom is formed at the end of the 3rd week as the intraembryonic mesoderm and either side of the midline...

Renal Agenesis and Ectopia

Unilateral Renal Agenesis Xray

Agenesis or ectopia of the kidney is frequently accompanied by characteristic malposition of specific portions of the bowel.16 Particular segments of the intestine may occupy the area of the renal fossa on the side of agenesis or ectopia, or show characteristic displacement and extrinsic mass effect by an ectopic kidney in as many as 75 of the cases.16,17 The clinical value of these observations is twofold 1. Identification of the characteristic intestinal malposition or displacement on a...

Anatomic and Normal Radiologic Features

Morison Pouch

The key to understanding the significance of the duo-denocolic relationships is the insertion of the root of the transverse mesocolon and its planes of reflection (Fig. 10-1). The hepatic flexure of the colon is characteristically composed of two curvatures.2 The proximal, more posterior one continues from the fixed extraperitoneal ascending colon and is related to the inferior and lateral edge of the right kidney and the posterolateral tip of the liver. The colon then passes immediately...

Axis of the Root of the Small Bowel Mesentery

The plane of attachment of the small bowel mesentery may be drawn by an imaginary line extending from the midtransverse duodenum or duodenojejunal junction to the ileocecal junction. The root of the mesentery most often inserts at the termination of the ileum with the colon and only rarely on the ascending colon or the distal ileum. On plain films, the line may be drawn from the left of L2 to the right sacroiliac articulation. The axis of the root may be defined more clearly by barium contrast...

Pathways of Extrapelvic Spread of Disease

Perinephric Extramedullary Hematopoiesis

Diseases arising from the pelvic contents may first manifest themselves by signs and symptoms remote from their source of origin. Gastrointestinal tract perforations, in particular, may dissect along anatomic planes of the pelvis to first present in the buttock, hip, thigh, and even the lower leg and the retroperitoneal space of the abdomen. Pain, mass, or crepitation at these sites may be very misleading since the origin of the underlying inflammatory condition or the neoplastic, traumatic, or...

Perirenal Extramedullary Hematopoiesis

Perirenal Lymphoma

Extramedullary hematopoiesis in myelofibrosis is widely distributed, involving organs such as the pleura, lungs, Spectrum of findings illustrated in four different patients. (a) Several discrete soft tissue nodules in the perirenal fat. (b) Confluent lobulated perirenal masses are associated with parenchymal involvement on the right. Note plaquelike thickening of Gerota's fascia and the bridging septa. (c) Massive perirenal lymphomatous mass on the left with displacement of the kidney,...

Small Bowel and Cecum

Pneumatosis Cecum

As the enzymes progress further down the root of the mesentery, jejunitis may be evident (Fig. 11-36). It has long been recognized that sentinel loops from localized paralytic ileus of small bowel may accompany pancreatitis.33 Jejunal and occasionally ileal changes characterized by marked persistent spasm of some segments and dilatation of others, with coarsening of the mucosal folds, may be seen (Figs. 11-37 and 11-38). Ischemic changes in the intestine as well may be produced by the digestive...

Duodenojejunal Junction Relation to Colon

Transvers Colon With Gas Within The Wall

The intimate relationship of the duodenojejunal junction superiorly to the root of the transverse mesocolon as it extends across the pancreas is of importance in the identification of both locally arising processes and remote colonic pathology. At this level, the mesocolon is generally long enough so that the transverse colon is considerably anterior. It is then apparent that minor effects on the distal transverse colon on an initial barium enema study may be shown to reflect a process that...

Pericecal Hernias

Peritoneal Fossae

Four peritoneal fossae in the ileocecal region as well as congenital and acquired defects in the mesentery of the cecum or appendix may lead to development of a pericecal hernia.7,9,19,73 The variety of other terms ileocolic, retrocecal, ileocecal, paracecal used to classify these hernias appear to have limited practical value in the radio-logic differential diagnosis and surgical management.16 In the collective review of 467 internal hernias by Hansmann and Morton,21 13 involved the ileocecal...

Management

Gastric Ulcer Images Black And White

Precise radiologic identification of an intraabdominal abscess permits the most appropriate route of drainage Fig. 3-12 . Although antibiotics play an important role, drainage remains the cornerstone of therapy. Radiographic localization is particularly important in supra-mesocolic infections. An abscess compartmentalized to the right posterior subhepatic space is classically drained surgically by Ochsner's extrapleural approach through the bed of the Fig. 3 122. Abscess of the falciform...

Perinephritis and Renointestinal Fistulas

Cross Section Fistula

Advanced perirenal infection may break through fascial boundaries to involve overlying bowel.6 The anatomic relationships of the kidneys, the enveloping fascial planes, and the colon are basic to an understanding of Fig. 9 22. Displacement of the left colon by left renal carcinoma. a and b Barium enema and CT show calcified left renal mass M producing anterior displacement of distal mesenteric transverse colon TC . The anatomic splenic flexure SF is maintained. Fig. 9 23. Displacement of left...

Transverse Colon and Splenic Flexure

Pics Gallstones After Colonic

Since Price's report, however, the term colon cut-off sign has lost its original definition and has been applied to multiple sites of spasm and narrowing of the colon secondary to pancreatitis. Stuart12 employed it to designate collapse with absence of gas in the midportion of the transverse colon, which appeared to be cut off from the gas-containing hepatic and splenic flexures. This was a constant finding in both supine and erect plain films of the abdomen in six patients with acute...

Retrorenal Plane Fluid Collections

Pancreatitis Fascia Renal Anterior

The dissectable, potential planes ofthe bilateral posterior renal fascia communicate with the bilateral retromesen-teric planes and lateroconal space, typically without involving perirenal fat and posterior pararenal fat Figs. 8112, 8-113, 8-115 . In the presence of ascites, fluid in the posterior peritoneal recesses may have a forktailed or wishbone configuration posterior to the kidney mimicking retrorenal and lateroconal plane fluid collec- tions.34535'150 This is probably related to the...

The Colon Normal and Pathologic Anatomy

Redundant Colon Picture

The distinctive haustral contour of the large intestine is provided by three bands of longitudinal muscle the taeniae coli. Since the taeniae are shorter than the length of the colon itself, their tethering action in relation to the circular muscle results in the characteristic haustral sacculations. The colonic haustra are thus organized into three distinct rows, each of which has characteristic anatomic relationships.1 The development and action of the taeniae have been carefully studied by...

Pancreas Divisum

Aneurismal Dilatation The Portal Veiv

Pancreas divisum is the most common congenital anomaly of the pancreas, occurring in approximately 5-10 of the population. Failure of the dorsal and ventral pancreatic primordia to fuse may result in separate draining of the ducts of Wirsung and Santorini Figs. 2-52 and 2-53 . Perhaps 25 of these develop pancreatitis secondary to stenosis or obstruction of one or both ducts, Fig. 2-44. Aneurysmal dilatation of the portal vein. A 62-year-old woman presented with abdominal pain. a Enhanced CT...

Transmesenteric and Transmesocolic Hernias

Colon Herniation Through Lesser Sac

About 5-10 of all internal hernias occur through defects in the mesentery of the small intestine.12'13'21 An etiologic relationship to prenatal intestinal ischemic accidents seems probable' because in infants with atretic intestinal segments such defects and herniation are frequently associated.14 In fact, nearly 35 of these hernias occur in the pediatric age group' in which they constitute the most common type of internal hernias.8'14 In adults, however' most mesenteric defects serving as the...

Sigmoid Colon Radiologic Features

Lower Colon Black

The sigmoid mesocolon reflects obliquely off the level of the left sacroiliac joint to suspend the redundant sig-moid loops anteriorly. It forms an inverted V with its apex located at the division of the left common iliac artery. The left portion descends medial to the left psoas major muscle.107,108 The right segment descends into the Fig. 4 115. Ascitic fluid collecting between mesenteric folds. a and b CT documents ascitic fluid pooling between the folds of the small bowel mesentery. The...

Normal Radiologic Observations

Double Contrast Barium Enema

The haustral recesses, bordered by the course of the taeniae, can be identified easily by routine barium enema examination, particularly with double contrast studies.1 Their distinctive organization into rows and the position and anatomic limits as well as the relationships of each row are clearly delineated. In the supine position, barium gravitates to the dependent posterior row of sacculations in the middle third. This outlines the TM-TO row in the ascending colon Fig. 15-8 and the TM-TL row...

Roentgen Anatomy of Distribution and Localization of Collections

Perirenal Pararenal Fat

Selective opacification of the anterior pararenal space in the cadaver permits identification of the preferential pathway of spread and the characteristic localizing features, as shown in Figure 8-40. Preferential flow is downward to the iliac fossa, and the collection demonstrates several diagnostic features 1. The general axis is vertical. 2. Medially, the collection overlaps the lateral border of the psoas muscle and approaches the spine. 3. Laterally, the lucent flank stripe is preserved,...

Distinction Between Intraperitoneal and Extraperitoneal Processes

Retrocecal Appendix

Figure 15-30 illustrates that in the ascending or descending colon, two of the haustral rows face intraper-itoneal structures. The TO-TL sacculations are in relation to the lateral paracolic gutter and the TM-TL row to the medial paracolic sulcus and the small bowel loops. Intraperitoneal processes in these areas, then, produce predominant changes on these haustra. In contrast, the posterior TM-TO row is unique in bearing relationship only to extraperitoneal processes, which are often...

Pancreatitis Falciform Ligament

Posterior Pararenal Fascia Collection

Extraperitoneal perforation of the descending duodenum following blunt trauma with anterior pararenal space infection. a Gastrografin GI series shows extravasation from the duodenum. Mottled gaseous lucencies extend inferiorly and laterally. Below the level of the cone of the renal fascia and the lateroconal fascia, the infection reaches and then ascends the flank fat arrows . b Pathway of spread inferior to the lateroconal fascia to communicate with the flank fat. Reproduced from...

T1 Stage

T1sm Staging

In the esophagus, the distinction of cancer involving only the mucosa T1m Fig. 5-8 from cancer invading the submucosa T1sm Figs. 5-9 and 5-10 may guide the application of endoscopic resection.33 Early gastric cancer may be defined on contrast-enhanced dynamic CT as an enhancing lesion with an intact low-density stripe at its base Fig. 5-11 . Figure 5-12 illustrates a thickening limited to the mucosal layer of the rectum with a normal muscularis mucosae representing a sessile adenoma, shown by...

Regional Enteritis

Antimesenteric Border

The general radiologic findings ofregional enteritis correlate closely with the gross pathologic features. The involved bowel, often affected by skip lesions, is sharply delimited from contiguous gut and has a narrowed lumen, which is sometimes strictured. The bowel wall is rigid and thick, the mesentery is often markedly thickened and edematous, and the mesenteric lymph nodes are enlarged. The swollen, inflamed mucosa develops a cobblestone appearance as longitudinal and transverse ulcers...

Detailed Anatomy of the Right Upper Quadrant

Morison Pouch

Since Barnard's original classification8 in 1908, a great deal of confusion in the definition and true anatomic Fig. 3-3. Rutherford Morison 1853-1939 . Morison, an English surgeon, is best known for the pouch that he described in The Anatomy of the Right Hypochondrium Relating Especially to Operations for Gallstones in 1894. He emphasized that bile leaks drain into this area but the external drain must extend to the very depths of the pouch. Courtesy of Wellcome Institute of the History of...

Gallium Scan Colon

Left Paracolic Gutter

Left subphrenic abscess from anterior gastric perforation. a Extensive scirrhous carcinoma of the stomach. b and c Following gastroscopy, with accidental perforation of the anterior gastric wall, repeat study shows contrast material extends from the stomach S anterior to the lesser omentum LO . It tracks to a large abscess arrow beneath the diaphragm and above the colon C , which is opacified by residual barium. Reproduced from Meyers.6 Fig. 3 90. Left subphrenic abscess,...

Effect of Gallbladder Disease on the Duodenocolic Relationships

Fistula Between Gallbladder And Duodenum

The nonspecificity of signs and symptoms of diseases of the gallbladder often makes a clinical diagnosis difficult. At times, it is the striking manifestation of the secondary effects on the neighboring bowel that first brings the patient to medical attention. Inflammatory adhesions may develop between the gallbladder and the postapical duodenum, permitting the development of fistulous communication Fig. 1019 . The gallbladder is closely applied to the superior as pect of the anterior hepatic...

Classification of Organization of Haustral Rows

Taenia Libera

Three distinct rows of haustral sacculations are thus produced Fig. 15-5 , which can be referred to by the taeniae that give their form 1. TM-TO. In the transverse colon, this row provides the superior mesenteric contour. Here the haustra bear two important relationships a they face the inferior recess of the lesser sac, providing its lower boundary, and Fig. 15 7. Postmortem double-contrast radiograph marked in situ with metallic clips. The change in both course and relative position between...

Internal Abdominal Hernias

Transmesenteric Internal Hernia

An internal abdominal hernia is defined as the protrusion of a viscus through a normal or abnormal aperture within the confines of the peritoneal cavity. The hernial orifice may be a preexisting anatomic structure, such as the foramen of Winslow, or a pathologic defect of congenital or acquired origin. The literature on the subject has been composed principally of case reports, often based on observations made at surgery or autopsy. The role of preoperative radiologic diagnosis of internal...

Internal Hernias

Umbilical Hernia Adults Untreated

An internal hernia is a protrusion of a viscus through a normal or abnormal aperture within the peritoneal cavity. Most internal hernias are the consequence of congenital anomalies of intestinal rotation and peritoneal attachment. Whereas they may occur in the pediatric age group, the majority are clinically encountered in a CT through the upper abdomen reveals a stomach with oral contrast delineating its posterior wall arrows . b CT through the pelvis of the same patient shows a multilobate...

The Gastrocolic Ligament

Diverticula Between Taenia

Figure 15-19 shows that processes extending along or arising within the gastrocolic ligament may be clearly identified by their specific effect on the transverse colon. Anatomic dissections have shown that the point of attachment of the gastrocolic ligament is actually within a couple of centimeters cephalad to the taenia omentalis. Injection experiments consistently demonstrate that the mesenteric plane of extension is preferentially upward along the TM-TO haustral row.5 This constitutes the...

Diverticulosis and Diverticulitis

Diverticula Vasa Recta

Colonic diverticula do not arise randomly from the circumference of the large intestine but tend to originate in four distinct rows Fig. 15-48 a on either side of the TM and b near the mesenteric borders of the TO and TL.5,21 These are related to the points of intramural penetration through connective tissue septa of the co-lonic wall.21 Their sites of origin from the TM-TL and TM-TO haustra can be identified clearly on routine radiographic studies Fig. 15-49 . Bona fide diverticula do not...

Scleroderma

Intestinal Scleroderma

In involvement of the small bowel by scleroderma, muscle atrophy results in atonicity and dilatation. Replacement of the atrophied muscle by collagen occurs in a patchy fashion, with perivascular accumulation in the submucosa. Accordion-pleating of the mucosal folds occurs in the face of luminal dilatation, resulting in a typical hidebound appearance.11 The individual folds are not thickened. At sites without sclerosis, areas of more normal or atrophic bowel may bulge out between the Fig. 14...

Carcinoid Tumors

Carcinoid Radiology

Almost 90 of intestinal carcinoids occur in the distal ileum.20,21 Invasion through the intestinal wall may stimulate an intense desmoplastic reaction in the surround ing submucosa and mesentery. A characteristic manifestation is a mesenteric mass with radiating linear strands22 Figs. 14-29 and 14-30 . Ileal carcinoids are multiple in approximately one- third of cases. Most comprise more than three lesions, while in a small percentage dozens of lesions of variable sizes may stud a discrete...

Intramural and Mesenteric Bleeding

Distal Ileum Mural Thickening

Bleeding into the wall of the small intestine and into the mesentery may be a consequence of many different disorders. It is seen in mesenteric thromboses and emboli, segmental ischemic disease, abdominal trauma, anticoagulation medication, underlying diseases associated with Fig. 14 36. CT comb sign of Crohn's disease in two cases. a Spiral CT demonstrates a distal ileal loop with mural thickening, including a curvilinear zone of fluid. Increased mesenteric fat is present in the right lower...

The Left Side

Compensatory Hyperplasia Liver

On the left side, there may be striking posteromedial malposition of the distal transverse colon. Normally, the highest portion of the large intestine in the left upper quadrant roentgenographic splenic flexure retains the mesenteric attachment of the transverse colon. Distal to this, it courses inferiorly between the medial surface of the spleen and the anterolateral aspect of the left kidney to the anatomic splenic flexure in relation to the splenic angle. The anatomic splenic flexure is...

Differential Diagnosis of Small Amounts of Subdiaphragmatic

Extraperitoneal Tissue

The predominant extraperitoneal gas within the posterior pararenal fat may seek the immediate subdiaphrag matic tissue planes. While occasionally extraperitoneal air may be distinguished by its outlining of individual diaphragmatic muscle bundles,274 I have observed two further characteristics at this site on erect films that are particularly useful in differentiating even small amounts of extraperitoneal gas from free intraperitoneal air 1. Free intraperitoneal air always conforms to the...

Hematogenous Metastases

Dynamic Ileus

The vasa recta of the bowel penetrate the wall on the mesenteric border. They then extend intramurally for variable distances before ramifying toward the antimes-enteric border to arborize into the rich submucosal plexus. The most common hematogenous metastasis to the small bowel clinically encountered is metastatic mela-noma.17 Its dissemination can be observed radiologically to follow, at times, the field of a specific arterial distribution.17 The embolic metastases typically present as Fig....

Psoas Abscess and Hematoma

Psoas Muscle Tumors

Spontaneous dissection from a primary site in the retro-fascial space deep to the transversalis fascia into the ex-traperitoneal compartments is rare.3 The iliopsoas compartment is an extraperitoneal space covered by the iliopsoas fascia. The greater psoas muscle originates from the transverse processes of T12 and the lumbar vertebrae and extends inferiorly to merge with the iliac muscle at the L5-S2 level, becoming the iliopsoas muscle. The iliopsoas muscle passes beneath the inguinal ligament...

Lymphatic Drainage of the Colon and Pathways of Lymph Node Metastasis

Regional nodal metastasis is one of the most common modes of tumor spread in carcinoma of the colon. The lymph nodes draining lymphatics from the colon can be classified into four groups the epicolic nodes, the para-colic nodes, the intermediate mesocolic nodes, and the principal nodes.16,17 The epicolic nodes lie on the wall of the colon beneath the peritoneum covering the colon, generally on the antimesocolic side of the colonic wall. The paracolic nodes lie along the marginal vessels along...

Prevesical Fluid Collection

Space Retzius Tumor

Because of the orientation of the umbilicovesical fascia, a prevesical fluid collection has a molar tooth configuration in an axial plane.285 The crown portion of the tooth lies anterior to the urinary bladder between the umbilicovesical fascia and transversalis fascia of the anterior abdominal wall and displaces the bladder posteriorly. The roots portion extends posteriorly between the fascia and either the peritoneum superiorly or the parietal pelvic fascia inferiorly, displacing the bladder...

Direct Invasion from Contiguous Primary Tumors

Distal Sigmoid Colon Mass

Intrinsic involvement of the alimentary tract by an immediately contiguous neoplasm indicates that a locally aggressive tumor has usually broken through fascial planes.84,85 The most common primaries arise in the ovary, uterus, prostate, and kidney. With pelvic tumors, the cardinal roentgen signs include an identifiable mass and invasion of the wall of adjacent bowel, often over a considerable length, usually without overhanging margins Fig. 4-86 . Tethering of mucosal folds is often a...

CT Anatomy of the Pancreatic Head

Pancreatic Vascular Anatomy

The vessels around the head of the pancreas can be identified on CT by following the course of the SMV, the gastrocolic trunk, the gastroduodenal artery, the posterior SPDA and SPDV, the anterior SPDA and SPDV, the proximal jejunal vessels, and the IPDA and IPDV Fig. 12-3 . These vessels form excellent anatomic landmarks around the head of the pancreas. At the level of the cranial portion of the head of the pancreas, the gastro-duodenal artery is located in the retropyloric space at the...

Lymphatic Drainage of the Stomach and Pathways of Lymph Node Metastasis

Lymphatic Drainage Stomach

The lymphatic drainage of the stomach consists of intrinsic and extrinsic systems. The intrinsic system in cludes intramural submucosal and subserosal networks, and the extrinsic system forms lymphatic vessels outside the stomach and generally follows the course of the arteries in various ligaments around the stomach.9,10 These lymphatic vessels drain into the lymph nodes at nodal stations in the corresponding ligaments and drain into the central collecting nodes at the root of the cellac axis...