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Micrograph stain of a parathyroid gland.

The parathyroid glands are small endocrine glands in the neck that produce parathyroid hormone. Humans have four parathyroid glands, which are usually located behind the thyroid gland, and, in rare cases, within the thyroid gland or in the chest. Parathyroid glands control the amount of calcium in the blood and within the bones.

The parathyroid glands are four or more small glands, about the size of a grain of rice, located on the posterior surface (back side) of the thyroid gland. The parathyroid glands are named for their proximity to the thyroid but serve a completely different role than the thyroid gland. They are quite easily recognizable from the thyroid as they have densely packed cells, in contrast with the follicle structure of the thyroid. However, at surgery, they are harder to differentiate from the thyroid or fat.

The glands were first discovered in humans by Ivar Viktor Sandström (1852-1889), a Swedish medical student, in 1880.[1]


  1. author = Eknoyan, G. "A history of the parathyroid glands". vol 26, pp. 801–7, Nov 1995


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