Third pharyngeal pouch, dorsal:
inferior parathyroid gland
Closely associated with
thymus primordium.
Detach together from
pharyngeal wall and travel
together; parathyroid bud
encased in thymic tissue.
When primordia pass thyroid
by 7th week, primordia
separate: inf. parathyroid
becomes located on infero-
posterior surface of thyroid.