Fig 1.

Surgical classification of parathyroid adenoma locations, anterior view. A, Superior, in proximity to the posterior surface of the thyroid parenchyma. B, Superior, fallen posteriorly into the tracheoesophageal groove and no longer in contact with the posterior surface of the thyroid tissue. C, Superior, fallen posteriorly into the tracheoesophageal groove and no longer in contact with the posterior surface of the thyroid tissue at the inferior pole close to the clavicles. D, Superior or inferior, in the midregion of the posterior surface of the thyroid parenchyma near the junction of the recurrent laryngeal nerve and the inferior thyroidal artery. E, Inferior, in the region inferior to the thyroid gland, lying in the anteroposterior plane of the thyroid and anterior to the trachea. F, Inferior, descended into the thyrothymic ligament or superior thymus and possibly appearing to be “ectopic” or in the mediastinum. G, Intrathyroidal.