Gross Anatomy USMLE Step 1 Practice Question
A 38-year-old man with a history of Crohn disease presents with severe perianal pain and fever (39.2°C). Vital signs show BP 128/82, HR 102, RR 18, SpO2 98% on room air. Examination reveals a fluctuant abscess in the ischioanal fossa. MRI confirms a 4×3 cm fluid collection. Lab work shows WBC 13,200/μL; blood cultures remain pending. He denies recent trauma. During surgical drainage, the surgeon carefully avoids the critical neurovascular structure traversing the lateral wall of this fossa. Which structure is at greatest risk of iatrogenic injury?
Answer choices
- AGreater sciatic foramen
- BFemoral canal
- CPudendal canalCorrect answer
- DObturator canal
- ELesser sciatic foramen
- FInferior rectal artery
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