Abdominal Anatomy: Solid and Hollow Organs, Quadrants, Peritoneum, and Retroperitoneum Practice Questions

25 multiple-choice questions on Abdominal anatomy: solid and hollow organs, quadrants, peritoneum, and retroperitoneum for paramedic and EMT students, from Chapter 37 (Abdominal and Genitourinary Trauma). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

25 practice questions

1. Which abdominal organ is classified as a hollow organ?

   1. A. Liver
   2. B. Stomach
   3. C. Spleen
   4. D. Pancreas
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   Answer: B. Stomach

   Hollow organs are tubes or sacs that carry or store material, such as the stomach, bowel, and bladder. The pancreas is a solid, glandular organ even though it secretes enzymes into a duct.

2. When a solid abdominal organ is injured, the main early danger is:

   1. A. Peritonitis from leaked bowel contents
   2. B. Bowel obstruction within minutes
   3. C. Immediate loss of bowel sounds
   4. D. Rapid, severe internal bleeding
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   Answer: D. Rapid, severe internal bleeding

   Solid organs such as the liver and spleen have a rich blood supply, so injury causes hemorrhage and shock. Peritonitis from spilled contents is the typical danger of hollow organ injury, not solid organ injury.

3. When a hollow abdominal organ ruptures, it causes harm mainly by:

   1. A. Bleeding briskly from its rich vascular network
   2. B. Compressing the vena cava against the spine
   3. C. Spilling contents that inflame the peritoneum
   4. D. Pushing the diaphragm up into the chest
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   Answer: C. Spilling contents that inflame the peritoneum

   Acid, bile, food, and feces leaking into the peritoneal cavity cause chemical and bacterial peritonitis. Hollow organs can bleed, but brisk hemorrhage is more typical of the vascular solid organs.

4. In adults with a stab wound that enters the abdominal cavity, the organ most often injured is the:

   1. A. Liver
   2. B. Pancreas
   3. C. Kidney
   4. D. Bladder
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   Answer: A. Liver

   The liver is large and occupies much of the upper abdomen, so it is the organ most often injured by stab wounds, followed by the small bowel, diaphragm, and colon. The pancreas and kidneys are deep and retroperitoneal, and the bladder is protected in the pelvis.

5. A woman at 34 weeks of gestation is stabbed in the lower abdomen below the umbilicus. Compared with a nonpregnant patient, the structure most likely injured is the:

   1. A. Spleen and the stomach
   2. B. Liver and gallbladder
   3. C. Kidneys and the ureters
   4. D. Uterus and the fetus
   Show answer

   Answer: D. Uterus and the fetus

   In late pregnancy the large uterus fills the lower and mid abdomen and pushes the bowel upward, so penetrating lower abdominal wounds usually strike the uterus and fetus while the mother's bowel is relatively shielded. Upper abdominal wounds, by contrast, can injure compressed bowel in several places. The spleen, liver, and kidneys are not in the path described.

6. A 34-year-old man was stabbed once in the right upper quadrant just below the rib margin. The solid organ most at risk is the:

   1. A. Liver
   2. B. Spleen
   3. C. Kidney
   4. D. Pancreas
   Show answer

   Answer: A. Liver

   The liver fills most of the right upper quadrant and extends under the lower right ribs, so it is the solid organ most at risk. The spleen is the main solid organ of the left upper quadrant, not the right. The kidney lies in the retroperitoneum and is more at risk from flank or back wounds. The pancreas lies deep in the retroperitoneum near the midline, behind the stomach, and is less exposed to a shallow upper quadrant stab.

7. A trauma patient who received large volumes of IV fluid now has a tense, distended abdomen, rising airway pressures on the ventilator, and almost no urine. You should suspect:

   1. A. Pulmonary edema from fluids
   2. B. Abdominal compartment syndrome
   3. C. Acute renal failure from hypotension
   4. D. Tension pneumothorax from ventilation
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   Answer: B. Abdominal compartment syndrome

   Bleeding, bowel swelling, and large-volume resuscitation can raise intra-abdominal pressure enough to push up the diaphragm (raising airway pressures), reduce venous return, and compress the kidneys (oliguria). This is abdominal compartment syndrome and needs surgical decompression. Pulmonary edema, a tension pneumothorax, or kidney failure can each explain one finding, but none explains the tense abdomen together with the high airway pressures and oliguria.

8. The sigmoid colon lies mainly in the:

   1. A. Right lower quadrant
   2. B. Right upper quadrant
   3. C. Left lower quadrant
   4. D. Left upper quadrant
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   Answer: C. Left lower quadrant

   The descending colon runs down the left side and becomes the sigmoid colon in the left lower quadrant. The appendix and cecum, not the sigmoid colon, are in the right lower quadrant.

9. During full exhalation, the dome of the diaphragm can rise as high as the:

   1. A. Fourth intercostal space
   2. B. Second intercostal space
   3. C. Eighth intercostal space
   4. D. Twelfth thoracic vertebra
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   Answer: A. Fourth intercostal space

   The diaphragm rises to about the fourth intercostal space (nipple level) on expiration, so wounds of the lower chest can enter the abdomen. Placing it at the eighth space or lower underestimates how high abdominal organs reach.

10. A 25-year-old was stabbed in the right side at the sixth rib in the midaxillary line. You should suspect injury to the:

    1. A. Lung and the spleen
    2. B. Lung and the liver
    3. C. Heart and the aorta
    4. D. Stomach and pancreas
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    Answer: B. Lung and the liver

    A wound below the nipple line can pass through the pleural space and the diaphragm into the abdomen, where the right side holds the liver. The spleen would be at risk with a similar wound on the left side.

11. The upper abdominal organs are partly protected by the:

    1. A. Iliac crests
    2. B. Sternum and clavicles
    3. C. Lower rib cage
    4. D. Lumbar transverse processes
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    Answer: C. Lower rib cage

    The liver, spleen, and stomach lie partly under the lower ribs, which is why lower rib fractures signal possible organ injury. The iliac crests surround the pelvic organs, not the upper abdomen.

12. A patient has a large hemoperitoneum but little abdominal tenderness. The best explanation is that:

    1. A. The peritoneum lacks sensory nerves
    2. B. Free blood clots over the pain fibers
    3. C. Shock blunts abdominal pain fibers
    4. D. Blood is a mild peritoneal irritant
    Show answer

    Answer: D. Blood is a mild peritoneal irritant

    Blood irritates the peritoneum far less than acid or feces, so a large bleed may cause few peritoneal signs. The parietal peritoneum is well supplied with sensory nerves, which is why spilled bowel contents are so painful.

13. The liver is especially prone to serious bleeding after trauma because it:

    1. A. Is large, vascular, and fixed in place
    2. B. Is mobile and swings on a pedicle
    3. C. Has a single end-arterial blood supply
    4. D. Lies mostly below the rib cage
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    Answer: A. Is large, vascular, and fixed in place

    The liver is the largest solid organ, holds a large blood volume, and is anchored by ligaments that tear on deceleration. It sits largely under the right lower ribs, is fixed rather than mobile on a pedicle, and has a dual (arterial and portal) blood supply, which adds to bleeding when it is torn.

14. A 58-year-old with cirrhosis has a liver laceration after a fall. Compared with a healthy patient, he is likely to bleed more mainly because he has:

    1. A. A shrunken spleen that stores fewer platelets
    2. B. Fewer clotting factors made by the liver
    3. C. Portal pressure that is lower than normal
    4. D. Excess vitamin K stored in the liver
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    Answer: B. Fewer clotting factors made by the liver

    The liver makes most clotting factors, so cirrhosis causes coagulopathy (often with low platelets from an enlarged spleen and portal hypertension), and an injured cirrhotic liver bleeds more and is harder to control. Cirrhosis enlarges the spleen rather than shrinking it, raises rather than lowers portal pressure, and impairs the use of vitamin K rather than adding to it.

15. Pancreatic injury is dangerous partly because the damaged gland releases:

    1. A. Bile that blocks the common hepatic duct
    2. B. Insulin that raises blood glucose
    3. C. Digestive enzymes into nearby tissue
    4. D. Urine into the retroperitoneum
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    Answer: C. Digestive enzymes into nearby tissue

    Leaking pancreatic enzymes digest the surrounding tissue and cause severe inflammation that may take hours to days to show. Insulin lowers rather than raises blood glucose, and bile comes from the liver.

16. The abdominal aorta and inferior vena cava lie in the:

    1. A. Peritoneal cavity
    2. B. Lesser omental sac
    3. C. Space anterior to the bladder
    4. D. Retroperitoneal space
    Show answer

    Answer: D. Retroperitoneal space

    The great vessels run along the spine behind the peritoneum, so bleeding from them may fill the retroperitoneum without peritoneal signs. They are not free within the peritoneal cavity.

17. A blow to the lower abdomen is more likely to injure the bladder in a 2-year-old than in an adult because in young children the bladder:

    1. A. Is protected behind the hips
    2. B. Sits higher, in the abdomen
    3. C. Is far smaller than the kidneys
    4. D. Is surrounded by thick fat
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    Answer: B. Sits higher, in the abdomen

    In infants and young children the bladder lies partly in the abdomen rather than deep in the pelvis, so it is less protected by the pelvic bones and more easily injured by lower abdominal blows. It descends into the pelvis with growth. Children have little abdominal fat to cushion it.

18. In a nonpregnant adult, the urinary bladder lies:

    1. A. Above the umbilicus
    2. B. Under the left costal margin
    3. C. Behind the pubic symphysis
    4. D. Behind the right kidney
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    Answer: C. Behind the pubic symphysis

    The empty bladder sits low in the pelvis behind the pubic bones, which is why pelvic fractures can tear it. A full bladder rises above the pubis and becomes more exposed to a blow.

19. The mesentery is important in trauma because it:

    1. A. Carries the blood supply to the bowel
    2. B. Anchors the kidneys to the spine
    3. C. Covers the front of the liver
    4. D. Divides the chest cavity from the abdomen
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    Answer: A. Carries the blood supply to the bowel

    The mesentery holds the vessels that supply the bowel, so a deceleration tear can cause both bleeding and bowel ischemia. It does not anchor the kidneys, which are fixed in the retroperitoneum by fat and fascia.

20. A 30-year-old was stabbed in the right lower back just below the twelfth rib. Which organ is at greatest risk?

    1. A. Spleen
    2. B. Stomach
    3. C. Sigmoid colon
    4. D. Right kidney
    Show answer

    Answer: D. Right kidney

    The kidneys lie in the retroperitoneum against the posterior abdominal wall at about T12 to L3. The spleen and stomach are left-sided and anterior to this wound path.

21. A 28-year-old woman was stabbed just above the left iliac crest. Which organ is most likely injured?

    1. A. Right kidney
    2. B. Gallbladder
    3. C. Descending colon
    4. D. Head of the pancreas
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    Answer: C. Descending colon

    The descending colon runs down the left flank just above the iliac crest. The gallbladder and right kidney are right-sided, and the head of the pancreas lies deep near the midline.

22. In a nonpregnant woman, the uterus and ovaries lie in the:

    1. A. Upper abdomen
    2. B. Left upper quadrant
    3. C. Space beside the kidneys
    4. D. Pelvic cavity
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    Answer: D. Pelvic cavity

    The uterus and ovaries are pelvic organs protected by the bony pelvis until pregnancy enlarges the uterus out of it. They do not normally sit near the kidneys or in the upper abdomen.

23. A 5-year-old fell onto his left side and has left upper quadrant tenderness, but his ribs show no fractures. Regarding a splenic injury, this means:

    1. A. It is ruled out by the intact ribs
    2. B. Still possible; child ribs bend
    3. C. Unlikely with no shoulder pain
    4. D. Unlikely without a high-speed mechanism
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    Answer: B. Still possible; child ribs bend

    A child's ribs are flexible, so force can be transmitted to the spleen and liver without breaking them, and solid organ injury without rib fractures is common in children. Intact ribs do not exclude splenic injury, referred shoulder pain is often absent, and a fall onto the side carries enough force; assess for shock and transport accordingly.

24. Before you arrive, a bystander pulled a knife out of a man's upper abdomen. He is alert with normal vital signs. You should:

    1. A. Assume organ injury; trauma center
    2. B. Clean the wound and release him at the scene
    3. C. Probe the wound with a finger to check depth
    4. D. Push the knife back into the original wound
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    Answer: A. Assume organ injury; trauma center

    The length and angle of a removed blade cannot be judged from the skin wound, and a normal initial exam does not exclude organ or vessel injury. Cover the wound, monitor for shock, and transport to a trauma center. Probing the wound and reinserting the knife are never appropriate.

25. Posteriorly, the kidneys are protected mainly by the:

    1. A. Lower ribs and thick back muscles
    2. B. Iliac crests and the sacrum
    3. C. Scapulae and paraspinal fat
    4. D. Liver and spleen lying on each side
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    Answer: A. Lower ribs and thick back muscles

    The kidneys sit high in the retroperitoneum under ribs 11 and 12, cushioned from behind by the heavy lumbar and paraspinal muscles and by perirenal fat. The iliac crests lie well below the kidneys and protect the pelvic organs, and the sacrum is lower still. The scapulae cover the upper back, far above the kidneys. The liver and spleen lie beside and in front of the upper poles, not behind them, so they do not shield the kidneys from a blow to the back.