The thyroid is a butterfly-shaped gland in the middle of the neck. It sits just below the larynx (voice box). The thyroid makes 2 hormones, called T3 and T4, which control how the body uses and stores energy. The parathyroid glands are 4 small glands behind the thyroid. They make a hormone called parathyroid hormone, which helps control the amount of calcium in the blood.
