Small Bowel Mesentery

The small bowel mesentery is a voluminous fat-laden peritoneal reflection. Whereas its root (Fig. 4-41) is only 15 cm long as it extends obliquely from the region of the pancreas to the right lower quadrant, the mesentery itself suspends 20-25 feet ofjejunal and ileal loops.72 This is achieved by its characteristic ruffled nature, which markedly lengthens its intestinal border. The mesenteric ruffles thereby provide routes of spread

Fig. 4—50. Spread of pancreatic carcinoma into the transverse mesocolon.

(a) Transaxial contrast-enhanced CT demonstrates a large mass in the tail of the pancreas encasing the splenic artery (arrowhead).

(b) Left-sided sagittal reconstruction shows spread of tumor along the transverse mesocolon (black arrowheads) to the gastro-colic ligament (white arrowheads). The renal artery (small arrow) and ovarian vein (large arrow) are also encased by tumor. M = pancreatic mass; P = normal pancreas; S = stomach; C transverse colon).

(Reproduced from Heiken et al.55)

Barnard LoopStellate Mesentery

to one or multiple small bowel loops (Figs. 4-76 and 4-77).

The normal small bowel mesentery is best appreciated on CT when its structural components are positioned to be imaged transaxially (Fig. 4-78). Its root is a bare area in continuity with the extraperitoneal anterior pararenal space.

These features also explain many of the characteristic growth patterns of mesenteric lymphoma. This may present or originate within the mesenteric root, and extension may be seen as multiple or conglomerate densities or a stellate infiltration7475 of the mesentery. Lym-

phomatous mural involvement of a small bowel loop specifically on its mesenteric border may then be noted73 (Fig. 4-79).

When mesenteric lymphoma coexists with paraaor-tic/paracaval adenopathy, a helpful differential feature on CT relies upon the integrity of the anterior pararenal fat. Even in the presence of a "sandwich sign" of a confluent lymphomatous mass infiltrating the mesenteric leaves and encasing the mesenteric vessels,76 there remains a visible plane of demarcation from commonly accompanying retroperitoneal adenopathy9 (Fig. 4-80).

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Fig. 4-51. Extension of pancreatic carcinoma into the transverse mesocolon, shown by interstitial-phase gadolinium-enhanced fat-suppressed T1-weighted MR images.

(a) A large cancer arises from the body of the pancreas (arrow).

(b) Tumor extends along the transverse mesocolon to involve the transverse colon (arrow). (Reproduced from Semelka et al.59)

Fig. 4-51. Extension of pancreatic carcinoma into the transverse mesocolon, shown by interstitial-phase gadolinium-enhanced fat-suppressed T1-weighted MR images.

(a) A large cancer arises from the body of the pancreas (arrow).

(b) Tumor extends along the transverse mesocolon to involve the transverse colon (arrow). (Reproduced from Semelka et al.59)

Duodenocolic Ligament

Fig. 4-52. Duodenocolic relationships.

(1) The hepatic flexure of the colon and the descending duodenum are bridged by the transverse mesocolon.

(2) The central lymph nodes draining the right colon are in relationship to the duodenum.

Fig. 4-52. Duodenocolic relationships.

(1) The hepatic flexure of the colon and the descending duodenum are bridged by the transverse mesocolon.

(2) The central lymph nodes draining the right colon are in relationship to the duodenum.

Fig. 4—53. Spread of carcinoma of right colon across duodenocolic ligament.

(a) Barium enema shows an annular carcinoma of the distal ascending colon (arrow). (b and c) CT scans demonstrate the mass (M) of the primary carcinoma and its spread across the duodenocolic ligament to para-duodenal-peripancreatic nodal masses (DC). D = duodenum. (Reproduced from Meyers et al.9)

Fig. 4—53. Spread of carcinoma of right colon across duodenocolic ligament.

(a) Barium enema shows an annular carcinoma of the distal ascending colon (arrow). (b and c) CT scans demonstrate the mass (M) of the primary carcinoma and its spread across the duodenocolic ligament to para-duodenal-peripancreatic nodal masses (DC). D = duodenum. (Reproduced from Meyers et al.9)

Paraduodenal Area And PictureParaduodenal Area And Picture

Fig. 4—54. Invasion of paraduodenal area across the mesocolon by colonic carcinoma.

(a) Upper gastrointestinal series demonstrates well-defined gas-containing abscess cavity (arrows) within a mass in the area of the head of the pancreas. Mucosal edema of the descending duodenum is present.

(b) A subsequent barium enema reveals a primary infiltrating carcinoma of the anterior hepatic flexure with opacification of a pericolonic-paraduodenal abscess (arrow).

(Reproduced from Treitel et al.57)

Paraduodenal Area And Picture

Fig. 4—55. Nodal spread from colonic carcinoma.

(a) Barium enema shows a polypoid carcinoma within the distal ascending colon.

(b) Upper gastrointestinal series documents metastases within the enlarged, draining lymph nodes by virtue of their extrinsic impressions upon the duodenum (arrows).

Fig. 4—55. Nodal spread from colonic carcinoma.

(a) Barium enema shows a polypoid carcinoma within the distal ascending colon.

(b) Upper gastrointestinal series documents metastases within the enlarged, draining lymph nodes by virtue of their extrinsic impressions upon the duodenum (arrows).

Fig. 4-56. Metastases within the draining central inferior mesenteric lymph nodes from a carcinoma of the left colon.

These are shown by the extrinsic pressure effect on the lateral aspect of the duodenojejunal junction (arrows).

Paradudenum And PictureParadudenum And Picture

Fig. 4-57. Metastases to paraduodenal lymph nodes from carcinoma of the ascending colon.

(a) Contrast-enhanced CT shows an annular carcinoma of the right colon (arrows).

(b) At a higher level, an enlarged paraduodenal lymph node with central necrosis (arrow) is evident. This lymphatic metastasis has occurred via the duodenocolic ligament.

(Courtesy of James Brink, M.D., Yale University School of Medicine, New Haven, CT.)

Fig. 4-57. Metastases to paraduodenal lymph nodes from carcinoma of the ascending colon.

(a) Contrast-enhanced CT shows an annular carcinoma of the right colon (arrows).

(b) At a higher level, an enlarged paraduodenal lymph node with central necrosis (arrow) is evident. This lymphatic metastasis has occurred via the duodenocolic ligament.

(Courtesy of James Brink, M.D., Yale University School of Medicine, New Haven, CT.)

Fig. 4-58. Metastatic paraduodenal node secondary to recurrent carcinoma of ascending colon.

A 6-cm nodal mass (M) is present anterior and lateral to the second portion of the duodenum (D). (Reproduced from McDaniel et al.63)

Fig. 4-58. Metastatic paraduodenal node secondary to recurrent carcinoma of ascending colon.

A 6-cm nodal mass (M) is present anterior and lateral to the second portion of the duodenum (D). (Reproduced from McDaniel et al.63)

Paraduodenal Node

Fig. 4-60. Lymphatic metastases to the duodenum from recurrent colon carcinoma.

CT reveals a large ulcerating lymphatic-borne metastasis in the third portion of the duodenum (arrows) associated with regional adenopathy (N).

(Courtesy of Kyunghee Cho, M.D., UMD-New Jersey Medical School, Newark, New Jersey.)

Fig. 4-60. Lymphatic metastases to the duodenum from recurrent colon carcinoma.

CT reveals a large ulcerating lymphatic-borne metastasis in the third portion of the duodenum (arrows) associated with regional adenopathy (N).

(Courtesy of Kyunghee Cho, M.D., UMD-New Jersey Medical School, Newark, New Jersey.)

Aortocaval Region

Fig. 4-59. Metastatic nodes along the principal superior mesenteric artery and in aortocaval region and small bowel mesentery with impressions upon duodenum secondary to carcinoma of the cecum.

(a) Metastatic lymph nodes in retroperitoneum, aortocaval nodal group (solid arrow) and mesentery (open arrow). Note compression upon third portion of duodenum (D).

(b) Metastatic nodes (arrow) near origin (arrowhead) of superior mesenteric artery. (Reproduced from McDaniel et al.63)

Fig. 4-59. Metastatic nodes along the principal superior mesenteric artery and in aortocaval region and small bowel mesentery with impressions upon duodenum secondary to carcinoma of the cecum.

(a) Metastatic lymph nodes in retroperitoneum, aortocaval nodal group (solid arrow) and mesentery (open arrow). Note compression upon third portion of duodenum (D).

(b) Metastatic nodes (arrow) near origin (arrowhead) of superior mesenteric artery. (Reproduced from McDaniel et al.63)

Fig. 4-61. Duodenoduodenal fistula.

Fifteen months following a right hemicolectomy for carcinoma of the hepatic flexure, upper GI series demonstrates the fistula (arrowheads), proved to be secondary to duodenal invasion by paraduodenal lymph node metastases.

(Reproduced from Schabel et al.66)

Paraduodenal NodeSmall Bowel Flow Fistula

Fig. 4-62. Duodenoduodenal fistula.

Eight years following a right hemicolectomy for carcinoma of the ascending colon, upper GI series shows multiple fistulous tracts (arrowheads) between the second and third portions of the duodenum (d) and jejunum (j) secondary to a large mass of ne-crotic paraduodenal tumor. (Reproduced from Schabel et al.66)

Fig. 4-62. Duodenoduodenal fistula.

Eight years following a right hemicolectomy for carcinoma of the ascending colon, upper GI series shows multiple fistulous tracts (arrowheads) between the second and third portions of the duodenum (d) and jejunum (j) secondary to a large mass of ne-crotic paraduodenal tumor. (Reproduced from Schabel et al.66)

Paradudenum And Picture

Fig. 4—63. The gastrosplenic and splenorenal ligaments.

(a) Anatomic cross sections at the level of T11 demonstrates the relationships of the gastrosplenic (GSL), splenorenal (SRL), and gastrocolic (GCL), ligaments. TC = transverse colon; DC = descending colon; St = stomach; P = pancreas; Go = greater omentum; Sp = spleen; LK = left kidney; Ao = aorta.

(b) Transverse diagram of the left upper quadrant shows the relationships of the gastrosplenic ligament (GSL) and splenorenal ligament (SRL).

Fig. 4—63. The gastrosplenic and splenorenal ligaments.

(a) Anatomic cross sections at the level of T11 demonstrates the relationships of the gastrosplenic (GSL), splenorenal (SRL), and gastrocolic (GCL), ligaments. TC = transverse colon; DC = descending colon; St = stomach; P = pancreas; Go = greater omentum; Sp = spleen; LK = left kidney; Ao = aorta.

(b) Transverse diagram of the left upper quadrant shows the relationships of the gastrosplenic ligament (GSL) and splenorenal ligament (SRL).

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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