A previously healthy 47-year-old woman comes to the emergency department because of a 2-week history of fatigue, abdominal distention, and vomiting. She drinks 6 beers daily. Physical examination shows pallor and scleral icterus. A fluid wave and shifting dullness are present on abdominal examination. The intravascular pressure in which of the following vessels is most likely to be increased?
Q32
A 23-year-old man is brought to the emergency department by a coworker for an injury sustained at work. He works in construction and accidentally shot himself in the chest with a nail gun. Physical examination shows a bleeding wound in the left hemithorax at the level of the 4th intercostal space at the midclavicular line. Which of the following structures is most likely injured in this patient?
Q33
A 39-year-old woman comes to the physician because of an 8-month history of progressive fatigue, shortness of breath, and palpitations. She has a history of recurrent episodes of joint pain and fever during childhood. She emigrated from India with her parents when she was 10 years old. Cardiac examination shows an opening snap followed by a late diastolic rumble, which is best heard at the fifth intercostal space in the left midclavicular line. This patient is at greatest risk for compression of which of the following structures?
Q34
A 12-year-old boy presents to the emergency department with severe abdominal pain and nausea. He first began to have diffuse abdominal pain 15 hours prior to presentation. Since then, the pain has moved to the right lower quadrant. On physical exam he has tenderness to light palpation with rebound tenderness. Lifting his right leg causes severe right lower quadrant pain. Which of the following nerves roots was most likely responsible for the initial diffuse pain felt by this patient?
Q35
A 27-year-old male is brought to the emergency room following a violent assault in which he was stabbed in the chest. The knife penetrated both the left lung and the left ventricle. Where did the knife most likely enter his chest?
Q36
A 12-year-old boy is brought to the emergency department late at night by his worried mother. She says he has not been feeling well since this morning after breakfast. He skipped both lunch and dinner. He complains of abdominal pain as he points towards his lower abdomen but says that the pain initially started at the center of his belly. His mother adds that he vomited once on the way to the hospital. His past medical history is noncontributory and his vaccinations are up to date. His temperature is 38.1°C (100.6°F), pulse is 98/min, respirations are 20/min, and blood pressure is 110/75 mm Hg. Physical examination reveals right lower quadrant tenderness. The patient is prepared for laparoscopic abdominal surgery. Which of the following structures is most likely to aid the surgeons in finding the source of this patient's pain and fever?
Q37
A 35-year-old male presents to the emergency room with difficulty breathing. He is accompanied by his wife who reports that they were eating peanuts while lying in bed on their backs when he suddenly started coughing profusely. He has a significant cough and has some trouble breathing. His past medical history is notable for obesity, obstructive sleep apnea, seasonal allergies, and alcohol abuse. He uses a continuous positive airway pressure machine nightly. His medications include cetirizine and fish oil. He has a 10 pack-year smoking history. His temperature is 98.6°F (37°C), blood pressure is 125/30 mmHg, pulse is 110/min, and respirations are 23/min. Which of the following lung segments is most likely affected in this patient?
Q38
A 27-year-old man is brought to the emergency department after a motorcycle accident 30 minutes ago. He was found at the scene of the accident with a major injury to the anterior chest by a metallic object that was not removed during transport to the hospital. The medical history could not be obtained. His blood pressure is 80/50 mm Hg, pulse is 130/min, and respiratory rate is 40/min. Evaluation upon arrival to the emergency department reveals a sharp metal object penetrating through the anterior chest to the right of the sternum at the 4th intercostal space. The patient is taken to the operating room immediately, where it is shown the heart has sustained a major injury. Which of the following arteries supplies the part of the heart most likely injured in this patient?
Q39
A 47-year-old woman comes to the emergency department after coughing up 2 cups of bright red blood. A CT angiogram of the chest shows active extravasation from the right bronchial artery. A coil embolization is planned to stop the bleeding. During this procedure, a catheter is first inserted into the right femoral artery. Which of the following represents the correct subsequent order of the catheter route?
Thorax/Abdomen US Medical PG Practice Questions and MCQs
Question 31: A previously healthy 47-year-old woman comes to the emergency department because of a 2-week history of fatigue, abdominal distention, and vomiting. She drinks 6 beers daily. Physical examination shows pallor and scleral icterus. A fluid wave and shifting dullness are present on abdominal examination. The intravascular pressure in which of the following vessels is most likely to be increased?
A. Inferior epigastric vein
B. Short gastric vein (Correct Answer)
C. Azygos vein
D. Gastroduodenal artery
E. Splenic artery
Explanation: ***Short gastric vein***
- This patient's heavy alcohol use, fatigue, abdominal distention with **ascites** (fluid wave, shifting dullness), and **scleral icterus** are highly suggestive of **decompensated cirrhosis** with **portal hypertension**.
- **Portal hypertension** causes blood to back up into the **splenic vein** and its tributaries, including the **short gastric veins**, leading to **gastric varices** which are prone to rupture and bleeding.
*Inferior epigastric vein*
- The inferior epigastric vein drains into the **external iliac vein** and is part of the systemic venous circulation, not directly impacted by portal hypertension.
- While systemic venous pressure can increase in conditions like heart failure, it's not the primary vessel affected by **portal hypertension** due to cirrhosis.
*Azygos vein*
- The **azygos vein** is a part of the systemic venous system in the chest and typically becomes engorged in conditions causing **superior vena cava obstruction** or severe right-sided heart failure.
- While it can indirectly become distended in severe portal hypertension through portosystemic shunts, the **short gastric veins** are more directly and significantly affected by elevated splenic vein pressure.
*Gastroduodenal artery*
- This is an **artery**, and arterial pressure is distinct from venous pressure; it is typically not directly increased due to cirrhosis and portal hypertension.
- Arteries carry oxygenated blood away from the heart, while the issue here is with venous drainage from the portal system.
*Splenic artery*
- This is an **artery** that supplies the spleen, and its pressure is not directly increased in **portal hypertension**.
- While the spleen itself can enlarge due to venous congestion (**splenomegaly**) from portal hypertension, this refers to changes in venous, not arterial, pressure.
Question 32: A 23-year-old man is brought to the emergency department by a coworker for an injury sustained at work. He works in construction and accidentally shot himself in the chest with a nail gun. Physical examination shows a bleeding wound in the left hemithorax at the level of the 4th intercostal space at the midclavicular line. Which of the following structures is most likely injured in this patient?
A. Right atrium of the heart
B. Inferior vena cava
C. Left upper lobe of the lung (Correct Answer)
D. Left atrium of the heart
E. Superior vena cava
Explanation: ***Left upper lobe of the lung***
- The **left upper lobe of the lung** extends to the 4th intercostal space at the midclavicular line, making it the most probable structure to be traversed by a penetrating injury at this location.
- The **pleural cavity** and lung tissue are superficially located in this region, making them highly susceptible to injury from a nail gun.
*Right atrium of the heart*
- The **right atrium** is located predominantly on the right side of the sternum, more centrally, and slightly to the right of the midclavicular line.
- An injury at the **left 4th intercostal space at the midclavicular line** would typically be too lateral and superior to directly injure the right atrium.
*Inferior vena cava*
- The **inferior vena cava (IVC)** enters the right atrium from below, primarily located within the abdomen and passing through the diaphragm at the level of T8.
- Its position is far too **inferior and posterior** relative to the 4th intercostal space to be directly injured by this wound.
*Left atrium of the heart*
- The **left atrium** is the most posterior chamber of the heart and is largely covered by the left ventricle.
- Although part of the heart is on the left, an injury at the **4th intercostal space, midclavicular line**, would likely impact the left ventricle or lung tissue before reaching the left atrium, which is located more posteriorly and medially.
*Superior vena cava*
- The **superior vena cava (SVC)** is located to the right of the midline, formed by the brachiocephalic veins behind the right first costal cartilage.
- Its position is too **medial and superior**, on the right side, to be directly injured by a nail penetrating the left 4th intercostal space at the midclavicular line.
Question 33: A 39-year-old woman comes to the physician because of an 8-month history of progressive fatigue, shortness of breath, and palpitations. She has a history of recurrent episodes of joint pain and fever during childhood. She emigrated from India with her parents when she was 10 years old. Cardiac examination shows an opening snap followed by a late diastolic rumble, which is best heard at the fifth intercostal space in the left midclavicular line. This patient is at greatest risk for compression of which of the following structures?
A. Trachea
B. Esophagus (Correct Answer)
C. Hemiazygos vein
D. Thoracic duct
E. Vagus nerve
Explanation: ***Esophagus***
- The patient's history of recurrent joint pain and fever in childhood, along with the cardiac exam findings of an **opening snap** followed by a **late diastolic rumble (best heard at the fifth intercostal space in the left midclavicular line)**, are classic for **rheumatic mitral stenosis**.
- **Mitral stenosis** leads to chronic elevation of **left atrial pressure**, causing **left atrial enlargement**. The **esophagus** lies directly posterior to the left atrium, making it susceptible to compression by an enlarged left atrium. Patients may present with **dysphagia** due to this compression.
*Trachea*
- The trachea is located anterior to the esophagus and typically superior to the heart at the level of the atria, making it less likely to be directly compressed by an enlarged left atrium.
- While significant cardiac enlargement can distort mediastinal structures, direct tracheal compression by an isolated enlarged left atrium is uncommon.
*Hemiazygos vein*
- The hemiazygos vein is located on the left side of the vertebral column in the posterior mediastinum and is not typically in close proximity to the left atrium in a manner that would lead to compression from left atrial enlargement.
- It drains into the azygos vein, which is more medially located, and its compression is not a recognized complication of isolated left atrial enlargement.
*Thoracic duct*
- The thoracic duct ascends in the posterior mediastinum, largely posterior and to the left of the esophagus. Its course makes it less susceptible to direct compression by an enlarged left atrium.
- Compression of the thoracic duct would typically lead to **chylothorax**, which is not associated with mitral stenosis.
*Vagus nerve*
- The vagus nerves (right and left) descend through the mediastinum in close proximity to the trachea and esophagus, but they are generally less vulnerable to direct compression by an enlarged left atrium compared to the esophagus.
- Compression of the left recurrent laryngeal nerve (a branch of the left vagus) can occur in cases of extreme left atrial enlargement (**Ortner's syndrome**), leading to **hoarseness**, but direct compression of the main vagus nerve itself causing broader symptoms is less common than esophageal compression.
Question 34: A 12-year-old boy presents to the emergency department with severe abdominal pain and nausea. He first began to have diffuse abdominal pain 15 hours prior to presentation. Since then, the pain has moved to the right lower quadrant. On physical exam he has tenderness to light palpation with rebound tenderness. Lifting his right leg causes severe right lower quadrant pain. Which of the following nerves roots was most likely responsible for the initial diffuse pain felt by this patient?
A. T7
B. L1
C. T10 (Correct Answer)
D. T4
E. C6
Explanation: ***T10***
- The initial **diffuse abdominal pain** in appendicitis is typically referred umbilical pain, which is mediated by the **T10 nerve root** due to the visceral afferent fibers primarily from the midgut.
- As the inflammation of the appendix progresses to involve the **parietal peritoneum**, the pain localizes to the right lower quadrant, corresponding to somatic innervation.
*T7*
- The **T7 nerve root** supplies innervation to the **epigastric region**, above the umbilicus, and is generally associated with conditions affecting the stomach or duodenum.
- This dermatome is too high to account for the initial visceral pain of appendicitis, which typically originates closer to the umbilical region.
*L1*
- The **L1 nerve root** primarily innervates the **inguinal region** and parts of the lower abdomen and hip.
- While relevant for conditions like groin hernias, it does not typically mediate the initial diffuse umbilical pain associated with appendicitis.
*T4*
- The **T4 nerve root** corresponds to the nipple dermatome and is associated with pain in the **chest wall** or upper abdomen, like esophageal pain.
- This dermatome is located significantly higher than the umbilical region and is not involved in the visceral pain pathway of appendicitis.
*C6*
- The **C6 nerve root** provides sensory innervation to the **thumb** and radial forearm, and motor innervation to muscles involved in wrist extension and elbow flexion.
- This nerve root is in the cervical spine and has no involvement in abdominal pain.
Question 35: A 27-year-old male is brought to the emergency room following a violent assault in which he was stabbed in the chest. The knife penetrated both the left lung and the left ventricle. Where did the knife most likely enter his chest?
A. Left fifth intercostal space in the midclavicular line (Correct Answer)
B. Left fifth intercostal space just lateral to the sternum
C. Left fifth intercostal space in the midaxillary line
D. Left seventh intercostal space in the midclavicular line
E. Left seventh intercostal space in the midaxillary line
Explanation: ***Left fifth intercostal space in the midclavicular line***
- The **apex of the heart**, predominantly formed by the **left ventricle**, is typically located in the **fifth intercostal space in the midclavicular line**.
- A stab wound in this location could therefore directly penetrate the **left ventricle** and the adjacent **left lung**.
*Left fifth intercostal space just lateral to the sternum*
- This location is closer to the **sternum** and would be more likely to damage the **right ventricle** or the **sternum** itself, rather than directly injuring the left ventricle and lung in a single penetration.
- The **left ventricle** is located more laterally, closer to the midclavicular line, especially at the apex.
*Left fifth intercostal space in the midaxillary line*
- The **midaxillary line** is too lateral to injure both the **left lung** and the **left ventricle** with a single penetrating stab in cases where the heart is in a normal anatomical position.
- While it would certainly penetrate the **left lung**, the heart is not anterior enough to be struck at this lateral position.
*Left seventh intercostal space in the midclavicular line*
- The **seventh intercostal space** is below the typical location of the **heart's apex** (fifth intercostal space).
- A stab wound here would likely hit the **diaphragm** or structures below it (e.g., spleen, stomach) rather than the heart.
*Left seventh intercostal space in the midaxillary line*
- This location is both too inferior and too lateral to simultaneously penetrate the **left lung** and **left ventricle** in a single stab.
- It would most likely injure the **diaphragm**, **spleen**, or the inferior aspects of the **left lung** (pulmonary base).
Question 36: A 12-year-old boy is brought to the emergency department late at night by his worried mother. She says he has not been feeling well since this morning after breakfast. He skipped both lunch and dinner. He complains of abdominal pain as he points towards his lower abdomen but says that the pain initially started at the center of his belly. His mother adds that he vomited once on the way to the hospital. His past medical history is noncontributory and his vaccinations are up to date. His temperature is 38.1°C (100.6°F), pulse is 98/min, respirations are 20/min, and blood pressure is 110/75 mm Hg. Physical examination reveals right lower quadrant tenderness. The patient is prepared for laparoscopic abdominal surgery. Which of the following structures is most likely to aid the surgeons in finding the source of this patient's pain and fever?
A. McBurney's point
B. Linea Semilunaris
C. Transumbilical plane
D. Arcuate line
E. Teniae coli (Correct Answer)
Explanation: ***Teniae coli***
- The **teniae coli** are three distinct longitudinal bands of smooth muscle that run along the length of the large intestine, converging at the base of the appendix. They serve as reliable anatomical landmarks for locating the appendix during surgery.
- Given the patient's symptoms (periumbilical pain migrating to the right lower quadrant, fever, vomiting, and right lower quadrant tenderness), **acute appendicitis** is highly suspected, making the teniae coli crucial for surgical identification of the inflamed appendix.
*McBurney's point*
- **McBurney's point** is a clinical landmark on the abdominal wall, two-thirds of the way from the umbilicus to the right anterior superior iliac spine, that often corresponds to the base of the appendix. It is used to elicit tenderness during physical examination.
- While tenderness at McBurney's point is a strong indicator of appendicitis, it is a **surface landmark** for diagnosis and not an internal anatomical structure that aids the surgeon in _finding_ the appendix during a laparoscopic procedure.
*Linea Semilunaris*
- The **linea semilunaris** is the curved tendinous intersection found at the lateral border of the rectus abdominis muscle, extending from the costal margin to the pubic tubercle.
- It defines the lateral extent of the rectus sheath but has **no direct anatomical relationship** to the appendix or its surgical identification.
*Transumbilical plane*
- The **transumbilical plane** is an imaginary horizontal plane passing through the umbilicus. It is used in topographical anatomy for abdominal segmentation.
- It is a **surface and arbitrary anatomical plane** for regional description, not an internal structure that guides surgical access to or identification of the appendix.
*Arcuate line*
- The **arcuate line** is a crescent-shaped anatomical landmark located on the posterior wall of the rectus sheath, inferior to the umbilicus, marking the transition where the aponeuroses of the transverse abdominis and internal oblique muscles pass anterior to the rectus abdominis.
- This line is relevant to the integrity of the rectus sheath but is **anatomically distant from the appendix** and does not assist in its surgical localization.
Question 37: A 35-year-old male presents to the emergency room with difficulty breathing. He is accompanied by his wife who reports that they were eating peanuts while lying in bed on their backs when he suddenly started coughing profusely. He has a significant cough and has some trouble breathing. His past medical history is notable for obesity, obstructive sleep apnea, seasonal allergies, and alcohol abuse. He uses a continuous positive airway pressure machine nightly. His medications include cetirizine and fish oil. He has a 10 pack-year smoking history. His temperature is 98.6°F (37°C), blood pressure is 125/30 mmHg, pulse is 110/min, and respirations are 23/min. Which of the following lung segments is most likely affected in this patient?
A. Posterior segment of right superior lobe
B. Inferior segment of right inferior lobe
C. Anterior segment of right superior lobe
D. Inferior segment of left inferior lobe
E. Superior segment of right inferior lobe (Correct Answer)
Explanation: ***Superior segment of right inferior lobe***
- The patient was found to be lying on his back while eating peanuts, which is a position that predisposes to aspiration into the **superior segment of the right inferior lobe**.
- Aspiration during supine positioning typically leads to foreign body entry into the most posterior-inferiorly directed airways.
*Posterior segment of right superior lobe*
- Aspiration into the **posterior segment of the right superior lobe** is less common in a supine position unless the patient is positioned slightly to the side.
- While the right lung is generally more prone to aspiration due to the straighter main bronchus, the specific segment depends on body position.
*Inferior segment of right inferior lobe*
- The **inferior segment of the right inferior lobe** would be more likely affected if the patient were in an upright position (e.g., sitting or standing) when aspiration occurred.
- In a supine position, gravity directs aspirated material more towards the superior segment of the inferior lobe.
*Anterior segment of right superior lobe*
- Aspiration into the **anterior segment of the right superior lobe** is rare regardless of body position during aspiration.
- This segment is anatomically less susceptible to gravitational flow of aspirated material compared to more posterior or inferior segments.
*Inferior segment of left inferior lobe*
- The **left main bronchus** branches at a sharper angle than the right, making aspiration into the left lung in general less common than into the right lung.
- If aspiration were to occur in the left lung, the specific segment would still largely depend on the patient's body position.
Question 38: A 27-year-old man is brought to the emergency department after a motorcycle accident 30 minutes ago. He was found at the scene of the accident with a major injury to the anterior chest by a metallic object that was not removed during transport to the hospital. The medical history could not be obtained. His blood pressure is 80/50 mm Hg, pulse is 130/min, and respiratory rate is 40/min. Evaluation upon arrival to the emergency department reveals a sharp metal object penetrating through the anterior chest to the right of the sternum at the 4th intercostal space. The patient is taken to the operating room immediately, where it is shown the heart has sustained a major injury. Which of the following arteries supplies the part of the heart most likely injured in this patient?
A. Right marginal artery (Correct Answer)
B. Left anterior descending artery
C. Left coronary artery
D. Posterior descending artery
E. Left circumflex coronary artery
Explanation: ***Right marginal artery***
- The right marginal artery typically arises from the **right coronary artery** and supplies the **right ventricle**.
- Given the injury location to the **right of the sternum** and the 4th intercostal space, the right ventricle is the most superficial and anterior chamber and thus the most likely to be injured.
*Left anterior descending artery*
- The left anterior descending artery supplies the **anterior** two-thirds of the **interventricular septum** and the anterior wall of the **left ventricle**.
- While located anteriorly, it is generally to the left of the sternum and would be protected by the more anterior right ventricle from an injury to the right of the sternum.
*Left coronary artery*
- The left coronary artery is a **short main stem** that quickly branches into the left anterior descending and left circumflex arteries.
- It is located more superiorly and to the left, making it less likely to be directly injured by a penetrating trauma to the **right of the sternum** at the 4th intercostal space.
*Posterior descending artery*
- The posterior descending artery supplies the **posterior** wall of both ventricles and the posterior one-third of the **interventricular septum**.
- This vessel is located on the posterior aspect of the heart, making it extremely unlikely to be injured by an anterior penetrating trauma.
*Left circumflex coronary artery*
- The left circumflex coronary artery supplies the **lateral and posterior walls of the left ventricle** and the left atrium.
- Its location on the posterior-lateral aspect of the heart makes it much less vulnerable to a penetrating injury coming from the **anterior chest**.
Question 39: A 47-year-old woman comes to the emergency department after coughing up 2 cups of bright red blood. A CT angiogram of the chest shows active extravasation from the right bronchial artery. A coil embolization is planned to stop the bleeding. During this procedure, a catheter is first inserted into the right femoral artery. Which of the following represents the correct subsequent order of the catheter route?
A. Thoracic aorta, right superior epigastric artery, right bronchial artery
B. Thoracic aorta, right bronchial artery (Correct Answer)
C. Thoracic aorta, left ventricle, left atrium, pulmonary artery, right bronchial artery
D. Thoracic aorta, brachiocephalic trunk, right subclavian artery, right internal thoracic artery, right bronchial artery
E. Thoracic aorta, right subclavian artery, right internal thoracic artery, right bronchial artery
Explanation: ***Thoracic aorta, right bronchial artery***
- The **femoral artery** leads directly into the **aorta**. From the aorta, the catheter can be navigated to the **thoracic aorta**, where the **bronchial arteries** typically originate.
- The **bronchial arteries** usually arise directly from the **descending thoracic aorta** (most commonly T5-T6 vertebral level) to supply the lung parenchyma and airways.
*Thoracic aorta, right superior epigastric artery, right bronchial artery*
- The **superior epigastric artery** is a terminal branch of the **internal thoracic artery**, supplying the anterior abdominal wall, and is not a direct path to the bronchial arteries.
- Navigating from the superior epigastric artery to the main bronchial artery without passing through intermediary large vessels would be anatomically incorrect and impractical.
*Thoracic aorta, left ventricle, left atrium, pulmonary artery, right bronchial artery*
- This path describes the venous and then pulmonary circulation (right heart, lungs), which is incorrect for reaching the **arterial system** of the bronchial arteries.
- A catheter inserted via the **femoral artery** remains within the arterial system and would not cross into the pulmonary circulation or the left heart chambers in this manner.
*Thoracic aorta, brachiocephalic trunk, right subclavian artery, right internal thoracic artery, right bronchial artery*
- This pathway involves ascending from the **thoracic aorta** to the **brachiocephalic trunk** and subsequently into the **right subclavian** and **internal thoracic arteries**, which is a route primarily to the upper limb and chest wall.
- While the internal thoracic artery can sometimes have small anastomoses, it is not the primary or direct route for embolizing a bronchial artery, which typically originates directly from the descending thoracic aorta.
*Thoracic aorta, right subclavian artery, right internal thoracic artery, right bronchial artery*
- Similar to the previous incorrect option, this route involves navigating through the **subclavian** and **internal thoracic arteries**, which is an indirect and unnecessarily complex path to the bronchial arteries.
- The **bronchial arteries** are direct branches of the **thoracic aorta**, making this a much more convoluted and less likely route for therapeutic embolization.
