USMLE Step 1 · USMLE Step 1: Medical Sciences

Anatomy, Embryology and Behavioral Science

18 practice questions, each with the answer and an explanation.

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Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 18 questions

  1. A woman has winged scapula after mastectomy. Which nerve was injured?
  2. A newborn has a defect that allows abdominal contents to herniate through the umbilical ring covered by a sac. What is the diagnosis?
  3. A newborn fails to pass meconium, and a rectal biopsy shows absence of ganglion cells. What is the cause?
  4. A 22-year-old has 2 weeks of decreased sleep, grandiosity and increased goal-directed activity. What is the diagnosis?
  5. A 35-year-old woman with a recent loss cannot sleep and has intense sadness but still enjoys some activities. This began 3 weeks after her mother died. What is the most likely diagnosis?
  6. A 3-week-old has projectile nonbilious vomiting and an olive-shaped mass. What is the diagnosis?
  7. A physician tells a patient the diagnosis only after asking how much the patient wants to know. Which ethical principle is being applied?
  8. A newborn has bilious vomiting and a double-bubble sign on X-ray. What condition is most likely?
  9. A baby has a murmur and cyanosis. Echo shows pulmonary stenosis, a ventricular septal defect, an overriding aorta and right ventricular hypertrophy. What is the diagnosis?
  10. A man has loss of the Achilles reflex. Which nerve root is mainly involved?
  11. A 50-year-old man has a wrist drop after sleeping with his arm over a chair. Which nerve is injured?
  12. A 2-year-old has a continuous machine-like murmur. Which drug closes the lesion?
  13. A runner has foot drop after a fracture of the fibular neck. Which nerve is injured?
  14. A man falls onto the lateral aspect of his shoulder and has weakness of abduction and sensory loss over the deltoid. Which nerve is injured?
  15. A 16-year-old requests contraception without parental consent. Which approach is correct in most states?
  16. A man has loss of the patellar reflex and weak knee extension. Which nerve root is mainly involved?
  17. A 40-year-old has episodes of intense fear with palpitations, sweating and a fear of dying that peak in 10 minutes. What is the diagnosis?
  18. A 70-year-old with metastatic cancer has capacity and refuses chemotherapy. What should the physician do?

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