Deck 8: The Blood Vessels of the Abdomen, Pelvis, and Perineum

Question 1

A 59-year-old man was involved in a head-on automobile accident. When seen in the emergency department, he was in hypovolemic shock and showed signs of extensive bruising on the lower part of the anterior abdominal wall. He was wearing a seat belt at the time of the accident. On examination, his abdomen was distended and tense; he had hypotension and tachycardia. A diagnosis of ruptured abdominal aorta was made during an emergency laparotomy. In cases of blunt traumatic injury to the abdominal aorta, do all patients become hypotensive immediately? Explain the possible role that the kidneys may play in causing damage to the aorta in deceleration injuries.

Answer 1

Frequently, patients with blunt rupture to the abdominal aorta may not immediately show signs of hypovolemic shock because the aorta is situated behind the peritoneum in the retroperitoneal space and the blood may not escape immediately into the peritoneal cavity (see text Fig. 5-62).
On impact, the patient may be held stationary by the seat belt, but the kidneys may continue forward until restrained by the vascular pedicles. Avulsion of the renal artery from the side of the aorta may take place under these circumstances.

Question 2

A 74-year-old man was seen in the emergency department complaining of the sudden onset of severe lumbar back pain. Three years previously he had had a myocardial infarction. On questioning, the patient admitted that he often experienced mild back and hip pains on getting up in the morning, but never had he experienced such a severe back pain. On examination, a somewhat tender pulsatile swelling could be felt in the abdomen at the level of the umbilicus. Both femoral pulses were present. A diagnosis of abdominal aortic aneurysm was made. What is the surface marking of the abdominal aorta? Explain why the back pain had started so suddenly and its significance. When an abdominal aneurysm ruptures, does an immediate fatal outcome always occur?
Into which hollow viscera or blood vessels may an aortic aneurysm rarely rupture into?

Answer 2

The abdominal aorta is a midline structure that enters the abdomen at the level of the twelfth thoracic vertebra, and its entrance may be projected onto the anterior abdominal wall just above the transpyloric plane (see text Fig. 8-3). The vessel extends downward to its bifurcation into the common iliac arteries at the level of the summit of the iliac crests.
The sudden onset of severe back pain can be explained by the aneurysm suddenly expanding or rupturing and pressing on the vertebral column, which lies immediately posterior to the aorta.
Death does not always immediately follow an abdominal aneurysm rupture. This can be explained by the fact that the hemorrhage may be initially confined to the retroperitoneal space, and a tamponade effect may temporarily prevent further bleeding.
The abdominal aorta is crossed by the third part of the duodenum, and cases have been reported of an aneurysm rupturing into the duodenal lumen. The inferior vena cava lies along the right side of the aorta, and an aneurysm has been known to rupture into it, producing a massive arteriovenous fistula.

Question 3

Explain in anatomic terms why penetrating injuries to the inferior vena cava are commonly fatal. Explain how it is possible to ligate the inferior vena cava below the level of the renal veins without adverse effects.

Answer 3

Penetrating injuries of the upper part of the inferior vena cava are commonly fatal because (a) the site of the injury is inaccessible behind the liver, duodenum, and the mesentery of the small intestine; (b) the presence of the right costal margin makes surgical access difficult; (c) the thin walls of the vena cava are likely to tear extensively and make repair difficult; and (d) the almost certain possibility that the liver is also damaged.
The extensive anastomosis of the lumbar veins with other retroperitoneal veins ensures that the blood is able to bypass the obstruction should the inferior vena cava be ligated below the level of the renal veins (see CD Fig. 8-3).

Question 4

A 63-year-old man with a long history of a duodenal ulcer was seen in the emergency department after vomiting blood-stained fluid and exhibiting all the signs and symptoms of severe hypovolemic shock.

-The following statements concerning duodenal ulcers could apply to the patient's condition except which?

A) Hemorrhage from a duodenal ulcer often reveals itself by the passage of black stools on defecation.
B) The pyloric sphincter prevents most of the blood from the duodenal lumen from passing up into the stomach.
C) The gastroduodenal artery lies behind the first part of the duodenum and was probably eroded by the ulcer.
D) The gastroduodenal artery is a small branch of the hepatic artery.
E) The duodenal ulcer was most likely to be situated on the posterior wall of the first part of the duodenum.

Question 5

A 58-year-old man was in a restaurant when he suddenly started to vomit blood. He was taken unconscious to the emergency department of a local hospital. On examination, he had all the signs of severe hypovolemic shock. On palpation of the anterior abdominal wall, the right lobe of the liver was felt three fingerbreadths below the costal margin. Several enlarged superficial veins could be seen around the umbilicus. His wife said that he had vomited blood 3 months previously and had nearly died. She admitted that he was a chronic alcoholic. The diagnosis was cirrhosis of the liver secondary to chronic alcoholism.

-The symptoms and signs displayed by this patient can be explained by the following statements except which?

A)The normal flow of portal blood through the liver is impaired by cirrhosis of the liver.
B) The portal-systemic anastomoses become enlarged in this condition.
C) At the lower end of the esophagus, a branch from the right gastric vein anastomoses with an esophageal tributary of the azygos vein.
D) Rupture of a varicosed esophageal vein could produce a severe hemorrhage so that the patient would vomit up blood.
E) With portal hypertension the paraumbilical veins linking the superficial veins of the skin (systemic veins) to the portal vein become congested and visible.

Question 6

A 56-year-old man visited his physician complaining that he experiences severe pain in both legs when taking long walks. He noticed recently that the cramp-like pain occurs after walking only a hundred yards. On questioning, he said that the pain quickly disappears on rest only to return after he walks the same distance. When the physician asked about his sex life the patient admitted that he was experiencing difficulty with erection.

-The symptoms and signs displayed by this patient can be explained by the following statements except which?

A)Arteriography of the abdominal aorta revealed blockage in the region of the bifurcation.
B) Only the right common iliac artery was involved by disease.
C) The gradual blockage of the aorta was caused by advanced arteriosclerosis.
D) An insufficient amount of blood was reaching both legs, causing pain (claudication) on walking.
E) The lack of blood entering both internal iliac arteries was responsible for the difficulty with erection.

Question 7

A 23-year-old woman, who was 8 months pregnant, told her obstetrician that she had recently noticed that her feet and ankles were swollen at the end of the day. She said that the swelling was worse if she had been standing for long periods. She also noticed that the veins around her ankles were becoming prominent.

-The symptoms and signs displayed by this patient can be explained by the following statements except which?

A) The enlarged uterus is an abdominal organ and often compresses the inferior vena cava.
B) Venous back pressure causes the tissue fluid to accumulate in the subcutaneous tissues of the feet and ankles.
C) Venous back pressure impairs the venous return in the superficial veins in both the legs, leading to varicose veins.
D) High levels of progesterone in the blood during pregnancy cause the smooth muscle in the wall of the veins to relax, thus permitting the veins to dilate.
E) The pregnant uterus presses on the sympathetic trunks, causing vasodilatation of the blood vessels of the legs.

Question 8

After complete occlusion of the origin of the inferior mesenteric artery with a blood clot, the blood supply of the left portion of the colon is maintained by the following arteries except which?

A) The marginal artery
B) The middle colic artery
C) The left lumbar arteries
D) Anastomoses between the superior, middle, and inferior hemorrhoidal arteries
E) Sigmoid arteries

Question 9

In patients with an obstruction of the superior vena cava, blood may return to the right atrium through the following anastomotic channels except which?

A) The lateral thoracic, lumbar, and superficial epigastric veins
B) The superior and inferior epigastric veins
C) The lateral thoracic, paraumbilical, and portal veins
D) The posterior intercostal and lumbar veins
E) The lateral thoracic veins alone

Question 10

If the common hepatic artery is unavoidably ligated during surgery, the arterial supply to the liver is maintained by the following anastomotic connections except which?

A) The superior pancreaticoduodenal artery anastomosing with the inferior pancreaticoduodenal artery
B) The right gastric artery anastomosing with the left gastric artery
C) The gastroduodenal artery anastomosing with the splenic artery
D) The esophageal arteries anastomosing with the inferior phrenic arteries
E) The right gastroepiploic artery anastomosing with the left gastroepiploic artery