Five measurements of blood oxygen saturation taken in a fetus are: 67, 61, 56, 52 and 31%.  The highest value is most likely recorded in which of the following vessels?

A 64-year-old man loses consciousness near the entrance to an emergency room.  A physician rushes to the patient and palpates a strong pulse along the inner side of the left sternocleidomastoid muscle.  The vessel palpated by the doctor is a derivative of which of the following aortic arches?

A 2-day-old infant is dusky and irritable.  He was born to a 22-year-old primigravida with sporadic prenatal care.  Delivery was uncomplicated, and Apgar scores were 7 and 8 at 1 and 5 minutes, respectively.  His temperature is 36.7 C (98 F), blood pressure is 70/30 mm Hg, pulse is 148/min, and respiratory rate is 68/min.  Physical examination shows a cyanotic and irritable newborn with mild-to-moderate respiratory distress.  Auscultation reveals a continuous, machine-like murmur appreciated between the scapulae.  Serum lactate is elevated.  Echocardiogram shows the aorta lying anterior, inferior, and to the right of the pulmonary artery.  Failure of which of the following embryologic processes is most likely responsible for this patient’s condition?

A 37-year-old woman is brought to the emergency department after developing sudden-onset right arm weakness and difficulty speaking.  She has no significant medical history but takes oral contraceptives.  Examination shows decreased right upper extremity strength and expressive aphasia.  Cardiac auscultation is normal.  MRI of the brain reveals acute infarction in the left frontal lobe.  Further evaluation to determine an etiology is performed.  During echocardiogram, agitated normal saline is injected into a peripheral vein and bubbles are seen passing into the left side of the heart.  Which of the following is the most likely cause of the observed finding in this patient?

A 47-year-old man is brought to the emergency department after being involved in a high-speed motor vehicle collision.  He was a restrained driver and rear-ended a slow-moving car on the highway.  He complains of chest pain, abdominal pain, and difficulty breathing.  The patient has a past medical history of hypertension, asthma, and type 2 diabetes mellitus.  On arrival, his blood pressure is 98/54 mm Hg and pulse is 121/min.  Thirty minutes later, he becomes unresponsive and his pulse is no longer detectable.  Electrocardiogram demonstrates sinus tachycardia.  Despite extensive resuscitation efforts, the patient dies.  An autopsy would most likely show an injury involving which of the following areas of the thoracic aorta?

A 55-year-old man is brought to the emergency department due to shortness of breath, productive cough, and confusion.  His wife mentions that last week he was diagnosed with the flu and his symptoms have progressively worsened.  Temperature is 39.4 C (103 F), blood pressure is 80/50 mm Hg, pulse is 120/min, and respiratory rate is 22/min.  Pulse oximetry shows 86% on room air.  On physical examination, the patient is obtunded and in respiratory distress.  He is intubated, given a 2-L bolus of normal saline, and started on broad spectrum antibiotics after blood cultures are obtained.  A central line is placed to access a structure embryonically derived from the common cardinal veins.  This structure is represented by which of the following labels shown in the chest CT scan below?

A 71-year-old man comes to the hospital due to 3 hours of persistent retrosternal chest pain and dyspnea.  After prompt evaluation, he is diagnosed with acute myocardial infarction and undergoes cardiac catheterization.  During cannulation of the right common femoral artery, the arterial wall is penetrated superior to the right inguinal ligament.  Percutaneous coronary intervention is then performed, after which firm pressure is applied to achieve hemostasis.  Soon after the procedure, the patient becomes cold, clammy, and hypotensive.  Physical examination shows a 5cm region of ecchymosis surrounding the femoral puncture site.  Internal bleeding is suspected.  Which of the following is the most likely location of the blood collection?

A 54-year-old man comes to the office due to episodic burning substernal chest pain.  His pain increases with activity and improves with rest.  The patient has a history of hypertension and hyperlipidemia.  He has smoked a pack of cigarettes daily for the past 30 years.  His blood pressure is 140/85 mm Hg and pulse is 76/min.  Cardiac auscultation reveals a S4 heart sound.  Lung and abdominal examinations are unremarkable.  An ECG at rest shows left ventricular hypertrophy.  A myocardial perfusion scan reveals inducible ischemia of the inferior surface of the heart.  Which of the following coronary arteries is most likely occluded in this patient?

A 45-year-old man comes to clinic due to frequent episodes of palpitations accompanied by dizziness, fatigue, and shortness of breath.  Prolonged ECG monitoring identifies episodes of atrial fibrillation associated with a rapid ventricular response rate.  A radiofrequency ablation procedure is planned.  The access site is the right femoral vein.  The ablation catheter is advanced to the left atrium where radiofrequency energy is used to eliminate an ectopic focus of abnormal electrical activity.  During the procedure, the catheter most likely passes through which of the following structures?

A 23-year-old previously healthy man is brought to the emergency department after a stab injury.  His friends report that they were “walking down the street minding our own business when a guy jumped out in front of us from behind a dumpster and stabbed him in the chest.”  They were able to disarm the man after this single attack, and the man then ran off into an alley.  The patient is conscious but in distress.  Physical examination shows a laterally directed anterior chest wall stab wound at the fifth intercostal space along the left midclavicular line.  Which of the following structures is most likely to have been injured in this patient?

A 35-year-old woman comes to the office due to solid food dysphagia for the past several months.  The patient has a sensation of food getting stuck in the mid-thorax, but has no pain or reflux.  She also has palpitations and dyspnea on exertion.  The patient immigrated to the United States from India 1 year ago, and was treated in her home country for rheumatic heart disease.  Barium esophagram demonstrates extrinsic compression on the mid-esophagus.  Enlargement of which of the following is most likely causing this patient’s dysphagia?

A 4-year-old boy is being evaluated for failure to thrive, shortness of breath, and exercise intolerance.  The parents first became aware of his symptoms after the patient started preschool a few weeks ago.  His teacher mentioned that the patient seemed to tire faster than the other children when playing outside.  Cardiac examination shows bounding peripheral pulses and a palpable thrill below the clavicle near the left upper sternal border.  On auscultation, a continuous murmur is best heard over the same region.  After discussion with the parents, a thoracotomy is scheduled to correct the patient’s condition.  During the procedure, the surgeon should plan on ligating a derivative of which of the following embryologic structures?

A 23-year-old woman is brought to the emergency department with a chest wound.  She was in her house during a severe thunderstorm when a large tree branch fell through a window.  The window was shattered and large fragments of wood and glass struck the patient.  She did not lose consciousness, but her family found her bleeding profusely and rushed her to the hospital.  Blood pressure is 80/50 mm Hg and pulse is 130/min.  The patient appears to be in severe distress.  Physical examination shows a deep penetrating wound in the fourth intercostal space along the left sternal border.  Smaller lacerations are noted across the face and forearms.  Which of the following structures is most likely injured in this patient?

A 65-year-old man with a history of coronary artery disease comes to the physician complaining of progressive exertional shortness of breath, fatigue, and lower extremity swelling.  His medical history is significant for a myocardial infarction 5 years ago and an electronic pacemaker implanted 2 years ago.  His chest x-ray is shown below.  A segment of one of the leads is highlighted (arrow).

The highlighted segment most likely lies within which of the following structures?

A 52-year-old man is brought to the emergency department for evaluation of fever, chills, and malaise.  Cardiopulmonary examination reveals a new holosystolic heart murmur that radiates toward the axilla.  Blood cultures are obtained, and the patient undergoes transesophageal echocardiography.  The ultrasound probe is placed in the midesophagus facing anteriorly, and the cardiac chambers are interrogated.

Item 1 of 2

Which of the following chambers is closest to the probe?

Item 2 of 2

In the same midesophageal position, the probe is rotated so that it now faces posteriorly.  Which of the following structures will be best visualized with the probe’s new orientation?

A 66-year-old man comes to the hospital due to sudden-onset chest pain and dyspnea.  The patient has a history of asthma and gastroesophageal reflux disease but says his current symptoms feel different than what he usually experiences.  An ECG is consistent with ST-elevation myocardial infarction, and an emergent cardiac catheterization is performed.  Evaluation of the left and right coronary arteries reveals left-dominant circulation.  A stenotic region is identified in one of the coronary vessels just before the origin of the artery supplying the atrioventricular node.  Which of the following arteries is most likely affected?

A 62-year-old man comes to the emergency department due to fever, productive cough, and dyspnea for the past several days.  His symptoms are becoming progressively worse.  The patient has underlying mild chronic obstructive pulmonary disease and has smoked a pack of cigarettes daily for the last 40 years.  On examination, temperature is 38.3 C (100.9 F), pulse is 110/min, and respirations are 24/min.  Auscultation of the right lung reveals bronchial breath sounds and crackles.  Laboratory evaluation shows leukocytosis.  Chest x-ray is shown below.

The mediastinal contour obscured by the lung consolidation on this patient’s chest x-ray is primarily formed by which of the following structures?