ABSTRACT
The thyroid gland is situated in the anterior triangle of the neck and lies deep to the strap muscles, namely, the sternothyroid and sternohyoid muscles. The bilobed gland overlies the second to the fourth tracheal rings and is connected by an isthmus. The paired inferior and superior thyroid arteries provide the arterial blood supply to the gland. Other important structures in proximity to the thyroid gland include the laryngeal nerves (superior and recurrent or inferior). Venous drainage is by three paired veins into the neck and superior mediastinum, and lymphatics drain into the nodal basins of the central and lateral compartments of the neck. The hormones secreted by the thyroid include triiodothyronine (T3), thyroxine (T4) and calcitonin. The parathyroid glands, which are usually four in number, are located in a position close to the capsule of the posterior aspect of the thyroid gland, regulate serum calcium. Understanding the anatomy is very critical for surgeons practicing thyroid surgery, so as to minimize life-threatening complications relating to the vasculature (bleeding), parathyroid glands (hypocalcemia and hypoparathyroidism) and nerve supply (palsy to the superior and recurrent laryngeal nerves).
