True regarding parathyroid glands except

The superior glands usually are dorsal to the RLN at the level of the cricoid cailage, Whereas the inferior parathyroid glands are located ventral to the nerve. They measure up to 7 mm in size and weigh approximately 40 to 50 mg each. Parathyroid glands usually derive their blood supply from branches of the inferior thyroid aery, although branches from the superior thyroid aery supply at least 20% of upper glands.