Embryology USMLE Step 1 Practice Question
A 4-day-old male is brought to the pediatric clinic because of breathing difficulties and poor feeding. He coughs, chokes, and spits up milk very soon after beginning to suckle. Physical examination and radiographs reveal the presence of the most common type of tracheoesophageal fistula. The infant's defect likely resulted from which of the following?
Answer choices
- AIncomplete formation of the septum secundum
- BPatent thyroglossal duct
- CIncomplete recanalization of the larynx
- DFailure of the tracheoesophageal ridges to fuseCorrect answer
- EFailure of the buccopharyngeal membrane to rupture
- FAbnormal migration of neural crest cells to the pharyngeal arches
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