Which adult structure is the sole derivative of the pharyngeal clefts?
- A Tympanic cavity
- B External acoustic meatus ✓
- C Palatine tonsil
- D Middle ear ossicles
Correct answer: B. External acoustic meatus
Explanation
Only the first pharyngeal cleft persists as a definitive structure, forming the external acoustic meatus. The second arch grows caudally over the remaining clefts, burying them in a temporary cervical sinus that normally obliterates; persistent cervical sinus gives rise to lateral neck branchial cysts and fistulae. The tympanic cavity and mastoid air cells derive from the first pharyngeal pouch, while the ossicles derive from the first (malleus, incus) and second (stapes) arch cartilages.
Reference: Langman's Medical Embryology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.