In 120 cadavers four parathyroid glands were found in 56.7% of cases. In most investigated specimens (above 90%) the superior parathyroid glands are localized posteriorly to the recurrent laryngeal nerve, whereas inferior parathyroid glands lie anteriorly to the nerve. The parathyroid glands are localized within a radius of 2 cm from the crossing of the recurrent laryngeal nerve and the inferior thyroid artery.