Mechanisms and Patterns of Abdominal Injury: Blunt and Penetrating Practice Questions

25 multiple-choice questions on Mechanisms and patterns of abdominal injury: blunt and penetrating 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. In blunt abdominal trauma, compression injury occurs when organs are crushed between the anterior abdominal wall and the:

   1. A. Pelvic floor
   2. B. Lower rib margin
   3. C. Diaphragm dome
   4. D. Vertebral column
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   Answer: D. Vertebral column

   A direct blow traps organs such as the pancreas, duodenum, and liver against the spine, crushing or bursting them. The diaphragm sits above the organs and does not provide a hard surface to crush against.

2. Deceleration forces typically tear abdominal organs at their:

   1. A. Thickest capsule areas
   2. B. Points of attachment
   3. C. Hollow central lumen
   4. D. Most anterior surfaces
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   Answer: B. Points of attachment

   When the body stops suddenly, mobile organs keep moving and shear at the ligaments, mesentery, and vascular pedicles that hold them. That is why the liver tears near its ligaments and the kidney at its renal artery.

3. A sudden, forceful rise in intra-abdominal pressure from a crushing blow can rupture the:

   1. A. Ureter
   2. B. Adrenal gland
   3. C. Diaphragm
   4. D. Femoral artery
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   Answer: C. Diaphragm

   A large pressure spike can tear the diaphragm and push abdominal contents into the chest, usually on the left because the liver shields the right. The ureter is small, mobile, and well protected, and is rarely injured by blunt force.

4. A restrained driver has a lap-belt bruise across the lower abdomen and midline low back pain. The spinal injury you should suspect is a:

   1. A. Jefferson fracture
   2. B. Chance fracture
   3. C. Hangman's fracture
   4. D. Boxer's fracture
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   Answer: B. Chance fracture

   A Chance fracture is a flexion-distraction fracture of the lumbar vertebra caused by the body jackknifing over a lap belt, and it often travels with bowel and mesenteric injury. Jefferson and hangman's fractures are cervical injuries.

5. After a 9-m (30-ft) fall, a man has left flank pain but no blood in his urine. Deceleration can still have torn the:

   1. A. Renal artery at its origin
   2. B. Ureter where it enters the bladder
   3. C. Adrenal medulla
   4. D. Urethra at the meatus
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   Answer: A. Renal artery at its origin

   The kidney swings on its vascular pedicle during deceleration, and the renal artery can tear or clot without causing hematuria. The absence of blood in the urine therefore does not rule out a serious renal injury.

6. A deceleration tear of the small bowel mesentery causes:

   1. A. Immediate rupture of the stomach
   2. B. Bile leak and chemical peritonitis
   3. C. Ischemia of the stomach and spleen
   4. D. Bleeding and bowel ischemia
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   Answer: D. Bleeding and bowel ischemia

   The mesentery carries the bowel's blood supply, so a tear both bleeds and cuts off flow to a bowel segment, which may later perforate. The small bowel mesentery does not supply the stomach, spleen, or biliary tree, so its tear does not cause gastric rupture, gastric or splenic ischemia, or a bile leak.

7. Compared with penetrating trauma, blunt abdominal trauma is often harder to recognize because:

   1. A. It rarely injures any solid organ
   2. B. Bleeding stops on its own in most cases
   3. C. Injuries may lie beneath intact skin
   4. D. Pain is limited to the point of impact
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   Answer: C. Injuries may lie beneath intact skin

   With blunt force there may be no wound to guide you, and the energy is spread over many organs. Blunt trauma commonly injures solid organs, which is the main reason it can cause hidden, fatal bleeding.

8. A low-energy knife wound to the abdomen injures tissue mainly:

   1. A. Along the path of the blade
   2. B. Through a large cavitation zone
   3. C. By a pressure wave in the bowel
   4. D. By shock waves through the liver
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   Answer: A. Along the path of the blade

   Stab wounds cause damage only where the blade cuts, so organ injury depends on location, depth, and angle. A cavitation zone is a feature of high-velocity bullets, not knives.

9. A 24-year-old was shot once in the abdomen with a handgun. Compared with a stab wound, a gunshot wound is more likely to:

   1. A. Spare the bowel because it is so mobile
   2. B. Stop at the abdominal wall muscle layer
   3. C. Limit injury to the entrance quadrant
   4. D. Penetrate the peritoneum and injure organs
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   Answer: D. Penetrate the peritoneum and injure organs

   Most abdominal gunshot wounds penetrate the peritoneum and injure organs, and bullets often travel unpredictably across quadrants. Many stab wounds, by contrast, never enter the peritoneal cavity.

10. A 26-year-old has a single handgun wound to the mid-abdomen, and the bullet has not exited. Based on known injury patterns in abdominal gunshot wounds, which organ is most likely injured?

    1. A. Liver
    2. B. Spleen
    3. C. Small bowel
    4. D. Urinary bladder
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    Answer: C. Small bowel

    The small bowel is the organ most often injured by abdominal gunshot wounds (about half of cases in ATLS data, with the colon next and the liver third), because its loops fill most of the abdominal cavity and a bullet often crosses them several times. The liver is the organ most often injured by stab wounds and is common in gunshot wounds, but it is not the most frequent one. The spleen is, with the liver, the organ most often injured by blunt trauma, not by gunshots. The urinary bladder sits protected in the pelvis and is injured mainly by low pelvic wounds or pelvic fractures. (ATLS 10th ed., Abdominal and Pelvic Trauma; Feliciano DV et al., Ann Surg 1988: small bowel 60%, colon 42%, liver 29% of 300 abdominal gunshot wounds.)

11. A 19-year-old was shot in the left buttock. He is pale and complains of lower abdominal pain. You should assume the bullet:

    1. A. Stopped in the gluteal muscle mass
    2. B. May have entered the abdomen or pelvis
    3. C. Injured the skin and sciatic nerve
    4. D. Exited without harm to deeper organs
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    Answer: B. May have entered the abdomen or pelvis

    Wounds of the buttock, flank, back, and lower chest can all reach the abdominal and pelvic organs, and pallor with abdominal pain suggests internal injury. Assuming the bullet stopped in the muscle would delay recognition of a vascular or bowel injury.

12. A 33-year-old was stabbed once in the left side of the back just below the tip of the scapula. The skin wound is small. You should assume the blade may have injured the:

    1. A. Paraspinal muscles and skin only
    2. B. Lung, diaphragm, and spleen
    3. C. Liver and the gallbladder
    4. D. Bladder and the rectum
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    Answer: B. Lung, diaphragm, and spleen

    The tip of the scapula lies at about the seventh rib. Below it, the pleura and lung extend several ribs lower and the diaphragm rises high on expiration, so a blade here can cross the pleura, lung, and diaphragm into the left upper quadrant, where the spleen (and, deeper, the left kidney) lies; treat it as a thoracoabdominal wound. Assuming the injury stops in the paraspinal muscles and skin is the classic error: thick back muscles slow a blade but do not stop it, and a small skin wound says nothing about depth. The liver and gallbladder lie on the right side. The bladder and rectum are pelvic organs far below this wound. (Caroline 9th ed., Abdominal and Genitourinary Trauma; ATLS 10th ed., thoracoabdominal and back wounds.)

13. A 15-year-old football player took a helmet blow to the left upper abdomen. He now feels faint and has left shoulder pain. This mechanism most likely caused:

    1. A. A rib fracture
    2. B. An appendix injury
    3. C. A splenic injury
    4. D. A left kidney contusion
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    Answer: C. A splenic injury

    A focused blow to the left upper quadrant can fracture the spleen, and blood under the diaphragm causes referred left shoulder pain. A rib fracture or kidney contusion does not explain faintness with referred shoulder pain, and the appendix lies in the right lower quadrant.

14. Why can a properly worn lap and shoulder belt still allow an abdominal injury in a high-speed frontal crash?

    1. A. The belt stretches and fails at speed
    2. B. The shoulder strap compresses the spleen
    3. C. Airbags push the belt into the pelvis
    4. D. Organs keep moving as the body stops
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    Answer: D. Organs keep moving as the body stops

    Even a well-restrained body decelerates abruptly, and the organs inside continue forward and tear at their attachments. Belts greatly reduce death and ejection; they cannot eliminate internal deceleration forces.

15. A worker was pinned at the waist between a forklift and a wall for several minutes. Which type of force caused his abdominal injuries?

    1. A. Compression
    2. B. Cavitation
    3. C. Blast overpressure
    4. D. Thermal energy
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    Answer: A. Compression

    Being squeezed between two objects compresses the abdomen and can burst hollow organs or fracture solid ones and the pelvis. Cavitation is the temporary cavity formed along a high-velocity bullet path.

16. A 27-year-old woman says her partner repeatedly kicked her in the abdomen. She is 24 weeks pregnant. You should recognize that:

    1. A. The fetus is protected by the bony pelvis now
    2. B. Abuse in pregnancy often targets the abdomen
    3. C. Kicks rarely injure the pregnant uterus
    4. D. Her injuries can be treated as minor
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    Answer: B. Abuse in pregnancy often targets the abdomen

    Intimate partner violence often increases during pregnancy and blows are commonly aimed at the abdomen, risking placental abruption. At 24 weeks the uterus is well above the pelvis and fully exposed.

17. A man was repeatedly stomped on the abdomen while lying on the ground. Compared with a single punch while standing, this mechanism is more dangerous because:

    1. A. Kicks spread force over a wider skin area
    2. B. Shoes absorb most of the transmitted energy
    3. C. Lying flat shields the abdominal organs
    4. D. The ground stops the body from moving away
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    Answer: D. The ground stops the body from moving away

    With the back against the ground, the abdomen cannot move with the blow, so the full energy is transferred to the organs, which are crushed against the spine. A standing victim can partly move with the force.

18. A 45-year-old has a seat belt sign across the lower abdomen but feels fine and has normal vital signs. Your best course is to:

    1. A. Treat it as possible bowel injury
    2. B. Reassure him that belt bruising is minor
    3. C. Release him once his vitals stay normal
    4. D. Recheck him if new pain develops later
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    Answer: A. Treat it as possible bowel injury

    A seat belt sign means enough force was transferred to injure bowel, mesentery, or lumbar spine, and hollow organ injuries often present late. Normal early vital signs do not rule these injuries out.

19. When a bullet strikes bone inside the abdomen, it most likely will:

    1. A. Stop without causing more harm
    2. B. Pass straight through unchanged
    3. C. Change direction and fragment
    4. D. Flatten and seal off its own tract
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    Answer: C. Change direction and fragment

    Bone deflects a bullet and can break both bullet and bone into fragments that act as secondary missiles, spreading injury in unpredictable directions. A bullet that strikes bone may stop, but the bone and bullet fragments add harm rather than ending it. Bone does not let a bullet pass through unchanged, so drawing a straight line from entrance to exit can miss injured organs. A bullet does not seal its tract; its cavity and fragments leave an irregular, contaminated wound.

20. A man was impaled on a metal rod that entered the perineum after a fall onto it. Organs at greatest risk include the:

    1. A. Spleen, stomach, and liver
    2. B. Kidneys, ureters, and adrenals
    3. C. Pancreas, duodenum, and aorta
    4. D. Rectum, bladder, and urethra
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    Answer: D. Rectum, bladder, and urethra

    An object entering the perineum travels into the pelvis, where the rectum, bladder, and urethra lie. Upper abdominal organs would be at risk only if the object traveled far upward.

21. Shearing injury of the abdomen is best described as tearing of organs by:

    1. A. Heat from a high-velocity bullet
    2. B. A pressure wave from an explosion
    3. C. Forces moving in opposite directions
    4. D. Crushing organs against the spinal column
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    Answer: C. Forces moving in opposite directions

    Shear occurs when one part of an organ or its attachment is held still while the rest keeps moving, producing a tear. Crushing against the spine is compression, a different blunt mechanism.

22. A child was run over by a slow-moving vehicle, and a tire mark crosses the lower abdomen. Which injury pattern should you anticipate?

    1. A. Isolated soft-tissue bruising
    2. B. Pelvic and abdominal organ crush injury
    3. C. Primary blast injury to the bowel
    4. D. Rotational injury of the cervical spine
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    Answer: B. Pelvic and abdominal organ crush injury

    Run-over injuries crush the pelvis and abdominal contents and can tear the liver, spleen, bowel, and bladder even with little external sign. Blast injury requires an explosion and is not part of this mechanism.

23. An 18-year-old was stabbed in the upper abdomen, and the knife is no longer present. The best predictor of possible depth is:

    1. A. The length of the weapon
    2. B. The width of the skin wound
    3. C. The amount of external blood
    4. D. The patient's pain rating
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    Answer: A. The length of the weapon

    Abdominal wall compression lets a short blade go deeper than expected, but knowing the weapon's length gives the best estimate of possible depth. A small skin wound tells you little about how far the blade traveled.

24. In a high-speed side-impact crash on the passenger's side, the passenger is most at risk for injury to the:

    1. A. Spleen
    2. B. Left kidney
    3. C. Sigmoid colon
    4. D. Liver
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    Answer: D. Liver

    Intrusion from the right side drives the door into the passenger's right lower ribs and the liver beneath them. The spleen and left kidney are at greatest risk when the impact is on the left.

25. Which finding at a crash scene should most raise your suspicion of intra-abdominal injury in a belted rear-seat passenger?

    1. A. A shoulder belt across the clavicle
    2. B. A headrest set at ear level
    3. C. A lap belt worn across the abdomen
    4. D. Child seats installed in the row
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    Answer: C. A lap belt worn across the abdomen

    A lap belt that rides up over the soft abdomen instead of the bony pelvis concentrates force on the bowel and lumbar spine. A shoulder belt across the clavicle and a correctly set headrest are proper positions.