Small Group Session I

(with answers shown in red)

Bed of the Stomach

Answer the following questions upon completion of your dissection of the stomach and
duodenum. (Questions A and B); Answer question C after the completion of the dissection of
posterior wall structures (kidneys, suprarenal glands etc.).

A. Carefully dissect the overlying large intestine from the underlying stomach and duodenum.
Identify each of the four subdivisions of the duodenum in your cadaver; including in your
description the length of each segment (cm.) , whether it is fixed (retroperitoneal) or free, and
vertebral level(s)

1) Superior part: 5 cm; proximal - free, distal- fixed. Extends from pyloris backward and superior to form a
cap to the right of Lumbar L1.2)

2) Descending part: 8-10 cm. Courses inferiorly along Lumbar 1,2 and 3, receiving contents of common bile
and pancreatic ducts. Is retroperitoneal. Overlies the hilum of right kidney and head of pancreas.

3) Horizontal part: 10 cm. Crosses Lumbar 3, the IVC and abdominal aorta. Is retroperitoneal. The SMA
crosses immediately anterior to it. It lies over the right ureter, right psoas and right genital artery.

4) Ascending part: 2.5 cm. Is at Lumber 2 on the left side of the aorta and supported by the suspensory
ligament (Lig. Of Treitz). The proximal part is fixed; the distal part is free as it communicates with the
proximal jejunum.

B. For each of the following ligaments that are attached or support the stomach; indicate the specific
names of the major structures (vessels, nerves, ducts, etc.) located within each.

1) Hepatogastric ligament: Left gastric artery/vein

2) Hepatoduodenal ligament: Portal vein, proper hepatic artery, common bile duct, autonomic nerve plexi
and lymphatics

3) Gastrocolic ligament: Contains right and left gastroepiploic vessels/auto.nerves.

4) Gastrophrenic ligament: Contains esophageal veins.

5) Gastrosplenic ligament: Contains left gastro-epiploic artery/vein, auto. nerves

6) Lienorenal ligament: Contains splenic artery.

7) Greater Omentum : Contains branches of the right and left gastroepiploic artery/vein, auto.nerves.

8) Phrenicolcolic ligament: Contains no named vessels.

8) Suspensory ligament of Duodenum: Contains striated muscles fibers derived from the right crus of the diaphragm.

8) Transverse mesocolon: Contains the middle colic artery/vein, and the continuation of the marginal artery,
auto.nerves.

C. Upon exposure of the posterior wall of the cadaver, replace into their relative positions, the stomach and
duodenum previously dissected. The "Bed of the Stomach" refers to all those major anatomical structures
that lie immediately behind the stomach. For example, this will include the left kidney and part of the
pancreas and major vessels. On the diagram below sketch in the relative position of the structures on your
cadaver that make-up the "Bed of the Stomach"

LIVER AND BILIARY SYSTEM

Answer the following questions upon completion of your dissection of the liver, biliary ducts
and pancreas.

A. Complete the drawing below of the drainage of the biliary tree as it occurs in your cadaver.
Be sure to include and label all ducts; including gall bladder, pancreas and duodenal papillae.
Note any variations from the normal pattern. Refer to Grant?s Atlas (Fig.2-83).

B. Identify the retro-hepatic space. With the body in the supine position, fluid in the peritoneal
cavity (acites) will accumulate in this area. Describe its boundary:

This space, also called the hepato-renal space, lies to the right of the T10-L1 vertebrae, is
bordered anteriorly by the inferior or visceral surface of the right hepatic lobe, and posteriorly
by the renal fascia/peritoneum covering the right kidney. Superiorly it is bounded by the coronary
ligament, adjacent to the "bare area" of the liver, inferiorly it is open to the greater peritoneal cavity.

C. One of the functions of the liver is to detoxify wastes of digestion. Such wastes are drained
from the large and small intestine through the portal veins into the sinusoids of the liver.
Cirrhosis of the liver replaces functional parenchyma with scar tissue and impedes portal blood
flow through the liver to the IVC. Examine your cadaver and describe at least two surgical
connections that can by-pass the portal flow through the liver.

(1) The "classic" portal-caval shunt is an anastomosis of the proximal part of the portal vein to the
IVC. Since that forces all of the blood to by-pass the liver, it is very toxic to the system. To reduce
the flow and relieve the pressure, the anastomosis of the proximal part of the splenic vein to the
IVC accomplishes the same by-pass with less difficulties. Alternatively, the splenic vein can be
connected to the left renal vein. What is important is the close anatomical relationship of the
respective veins with one another that allows an easy anastomosis.

(2) A second procedure is to place a "stent" into the liver. These are constructed either of stainless
steel, or a stiff synthetic material that is placed within the sinusoids to shunt blood through a diseased
area from the portal blood directly into a hepatic vein. Several stents may be used. It relieves the
pressure, and can be done as a non-invasive surgical procedure.

Patients suffering from reduced blood flow through the liver commonly will exhibit vericosities
or enlargement of veins as portal venous blood attempts to seek alternate pathways through
systemic veins to return to the heart. Where are the four major connections located and what
would be the complaint of the patient for each?

(1) Hemorrhoids or varicosities formed by enlargement of the thin venous wall of the connections
between the superior rectal vein (portal) and the middle rectal veins (systemic). Causes bleeding
as bright red blood in the stools. Corrected easily by surgery.

(2) Esophageal varicosities formed by increased portal blood flowing in the esophageal veins (systemic)
that drain into the Azygos vv.; and communicate with the gastric/esophageal veins (portal) of the
stomach. Veins lie deep to the esophageal mucosa, and will form varicosities that project into the
esophageal lumen. Patients will cough up blood; is difficult to control and patients may "bleed out".
Procedure to stop flow is to insert an esophageal balloon to increase pressure on veins.

(3) "Caput medusae" or the formation of varicosities beneath the skin that radiate from the umbilicus.
Formed as a consequence of a patent umbilical vein (portal) that communicates with the superficial
veins of the abdomen around the umbilicus (systemic). Also seen in patients with typhoid fever with
impaired liver function. Patients complain that they can't wear a bikini on the beach.

(4) Veins of Retzius. Varicosities formed on the posterior wall of the abdomen due to enlargment of
the left colic veins (portal), pancreatic veins (portal) with the lumbar segmental veins (systemic). While
an alternate pathway, they are not clinically significant since patients will not perceive a difficulty.

D. Understand the concept of a physiological or hepatic lobes compared to an anatomical lobe.

(1) Describe the course of travel of an infection from a diverticula of the sigmoid colon to the liver;
naming all venous tributaries.

Venous drainage of the sigmoid colon via sigmoid vv., inferior mesenteric v. splenic v., portal v. to left
hepatic lobe.

(2) Describe the course of travel of an infection from an inflamed appendix to the liver.

Venous drainage of the appendix via the appendicular v., iliocolic v., superior mesenteric v., portal v.,
to the right hepatic segment.

E. Describe the attachments and contents of the two major peritoneal supports of the spleen.

The spleen is supported by the lieno-renal and gastro-lienal ligaments. The lieno-renal liagment is a
peritoneal reflection at the level of the left kidney (one layer on the lesser sac side, the other layer on
the greater peritoneal sac side) that attaches to the hilum of the spleen. It contains the splenic artery
and the tail of the pancreas. The Gasro-lienal ligament is a peritoneal reflection from the greater
curvature of the stomach to the spleen, and contains the left gastroepiploic artery and vein.

F. Upon completing the dissection of the pancreas; examine the presence of an accessory
pancreatic duct on your cadaver. Does your cadaver have an accessory duct ? Yes or No
Based on that observation, in the living condition, what would be the consequences of a gall
stone becoming impacted in the duodenal ampulla in this cadaver.

If the answer is No, a gall stone would likely occlude the major duodenal papilla; thus, preventing
drainage of both the hepatic ducts and the pancreatic ducts. If the answer is Yes, then the drainage
of the hepatic ducts is affected, while there is an alternate drainage pattern for the pancreatic ducts
through the accessory pancreatic duct. It is possible that some drainage of bile can also retrograde
back through the accessory duct.