Which pharyngeal pouch forms the inferior parathyroid gland?

• A. Third pharyngeal pouch
• B. Fourth pharyngeal pouch
• C. Second pharyngeal pouch
• D. First pharyngeal pouch

Answer: (A)

Inferior parathyroid glands come from the dorsal part of the third pharyngeal pouch, which also forms the thymus from its ventral part. As development proceeds, the thymus descends into the chest and the inferior parathyroids travel with it, ending up near the lower pole of the thyroid. This migratory pattern explains why these glands are located lower than the superior parathyroids. The fourth pharyngeal pouch gives rise to the superior parathyroids (and contributes to other structures), while other pouches form different tissues like the middle ear and palatine tonsil, underscoring why the third pouch, not the others, is responsible for the inferior parathyroids.