How is parathyroid embryology?

Inferior (-The inferior parathyroid glands = PIII, because they arise from the dorsal wing of the third pharyngeal pouch -This common origin is why the PIII = thymic parathyroids and the two structures are described as the parathymus) Superior (-The superior parathyroid glands are also known as PIV, because they arise from the fourth pharyngeal pouch -The fourth pharyngeal pouch giving rise to the ultimobranchial body -Due to this close origin with the lateral thyroid, the superior parathyroids are sometimes called the thyroid parathyroids However, it migrates far less than the PIII -Because of the shorter migration length, PIV are in a more constant location than the PIII -The PIV are generally located more posterior and medial than the PIII -Histologically= chief cells and oxyphil cells)