The thyroid is a small, butterfly-shaped gland located at the base of your neck just below the Adam’s apple. It’s part of an intricate network of glands called the endocrine system. The endocrine system is responsible for coordinating many of your body’s activities. The thyroid gland manufactures hormones that regulate your body’s metabolism.

Several different disorders can arise when your thyroid produces too much hormone (hyperthyroidism) or not enough (hypothyroidism).

Four common disorders of the thyroid are Hashimoto’s disease, Graves’ disease, goiter, and thyroid nodules.

Graves’ disease is the most common cause of hyperthyroidism, affecting about 70 percent of people with an overactive thyroid. Nodules on the thyroid — a condition called toxic nodular goiter or multinodular goiter — can also cause the gland to overproduce its hormones.