Embryology USMLE Step 1 Practice Question
A 2-week-old female infant is found to have imperforate anus (no anal opening) on physical examination. Imaging reveals the rectum ends in a fistula that connects to the urethra. This defect suggests abnormal development of the cloacal membrane and urorectal septum. Which of the following weeks of embryonic development is most critical for this process?
Answer choices
- AWeeks 12-16
- BWeeks 20-24
- CWeeks 4-7Correct answer
- DWeeks 8-10
- EWeeks 1-2
- FWeeks 16-20
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