Thymus develops from
Pharyngeal pouchDerivativesDorsal ends of I and II pouches form --Tubotympanic recessThe proximal pa of tubotympanic recess gives rise to auditory tube.Distal pa gives rise to tympanic cavity and mastoid antrum. Mastoid cellsdevelop at about 2 years of ageVentral pa of II pharyngeal pouchEpithelium covering the palatine tonsil and tonsillar crypts, lymphoid tissueis mesodermal in originIII Pharyngeal pouchThymus and inferior parathyroid gland or parathyroid III.IV Pharyngeal pouchSuperior parathyroid or parathyroid IVV Pharyngeal pouch (ultimobranchial body)Parafollicular or 'C' cells of the thyroid glandRef: Chaurasia; Volume 3; 6th edition; Page no: 30
I Pharyngeal pouch
II Pharyngeal pouch
III Pharyngeal pouch
IV Pharyngeal pouch
Head and neck