Figure 2.

Intraoperative figures description of types of parathyroid gland. (A) Type A1 parathyroid gland locates next to thyroid gland and outside of thyroid capsule (white arrow). (B) Type A2 parathyroid gland is partially or totally embedded in thyroid gland and locates outside of thyroid capsule (white arrow). (C) Type A3 parathyroid gland locates in the resected thyroid gland (white arrow). (D) Type B1 parathyroid gland locates in the central compartment and around thyroid gland, but had no close relationship with thyroid gland (white arrow indicates type B1 parathyroid gland and blue arrow indicates type A1 parathyroid gland). (E) Type B2 parathyroid gland locates in thymus parenchyma (white arrow indicates type B2 parathyroid gland and blue arrow indicates type B3 parathyroid gland). (F) Type B3 parathyroid gland locates within thyrothymic ligament, which is mainly supplied by the vessels of thymus or mediastinum (white arrow).