Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. Parathyroid glands control the calcium in our bodies--how much calcium is in our bones, and how much calcium is in our blood. Calcium is the most important element in our bodies (we use it to control many systems), so calcium is regulated very carefully. Parathyroid glands control the calcium.
Parathyroid glands (we all have 4 of them) are normally the size of a grain of rice. Occasionally they can be as large as a pea and still be normal. The four parathyroids are shown in this picture as the mustard yellow glands behind the pink thyroid gland. Normal parathyroid glands are the color of spicy yellow mustard. The light blue tube running up the center of the picture is the trachea (wind pipe). The voice box is the pink structure at the top of the picture sitting on top of the trachea. The carotid arteries are shown on both sides of the thyroid running from the heart up to the brain. NOTE: we are looking at the back side of the thyroid so we can see the parathyroids. Remember, the parathyroids are behind the thyroid. Also note that this drawing shows three small (normal) parathyroid glands and one big diseased one--this is the typical situation of a patient with parathyroid disease--one of the parathyroid glands grows into a tumor and makes too much hormone. If you have parathyroid disease, you very likely have 3 normal parathyroid glands the size of a grain of rice and one parathyroid tumor that is as big as an olive, grape, or even a walnut. If you have parathyroid disease (hyperparathyroidism) you will need an operation to remove the one parathyroid gland which has become a tumor. More about parathyroid disease on other pages...this page is about NORMAL parathyroid function. One more introductory note... We must make sure you understand that the thyroid and parathyroid are NOT related. Although they are neighbors and both are part of the endocrine system, the thyroid and parathyroid glands are otherwise unrelated--they do not have the same function--just similar and confusing names!