The parathyroid glands are located on the back of the thyroid gland, usually one above and one below, with a total of 4 on the left and right (the number varies from person to person, with 3 to 8 reported in the literature). Normally, they are the size of a grain of rice, flat and ovoid, and morphologically resemble fatty granules and lymph nodes.
The parathyroid glands may be small, but they do a lot. They secrete parathyroid hormone (PTH), which regulates the balance of calcium and phosphorus metabolism in our bodies and raises blood calcium levels in the bones, kidneys, and other organs. In turn, calcium ions are essential for maintaining normal muscle and nerve function.
Co-written by Dr. Jiaqian Hu, Cancer Hospital, Fudan University