The Location of the Thyroid and Parathyroid Glands

Several organs are found in the neck. The thyroid gland is located in the anterior portion of the neck, in front of the trachea’s 2nd, 3rd, and 4th C-shaped cartilaginous pieces and below the larynx. It’s made up of two lobes, left and right, that are connected by an isthmus and covered by a fibrous capsule and then by a fascial capsule.

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The thyroid gland helps regulate metabolism by producing two hormones called thyroxine and triiodothyronine. It also produces thyrocalcitonin, which helps regulate the levels of calcium in your blood.

The thyroid gets its blood supply from the superior and inferior thyroid arteries. Its nerve supply comes from the superior, middle, and inferior cervical sympathetic ganglia. Lymphatic fluid from the thyroid drains into the deep cervical lymph nodes.

The following thyroid disorders can cause the thyroid gland to secrete too much or too little thyroid hormone:

  • Hyperthyroidism is the condition when the thyroid gland produces too much of the hormones. It can be caused by getting too much iodine, as a result of Graves’ disease (an immune-system disorder), inflammation of the thyroid due to infections, or tumors. Symptoms of hyperthyroidism include increased sweating, weight loss, feeling too hot, feeling nervous and restless, goiter (visibly enlarged thyroid gland), and difficulty concentrating. It’s diagnosed by blood tests that measure the thyroid hormones and thyroid-stimulating hormone that’s produced by the pituitary gland. Hyperthyroidism can be treated by surgery or medications that slow the thyroid down.

  • Hypothyroidism is the opposite condition, in which the thyroid gland doesn’t secrete enough of the hormones. It’s usually due to low levels of iodine and inflammation of the thyroid gland due to autoimmune reactions. It can also be due to radiation exposure, thyroiditis, or pregnancy.

Four parathyroid glands are nestled behind the thyroid gland (two on each side) and are covered with the same fascial capsule as the thyroid. The top two superior parathyroid glands are located at the level of the bottom of the cricoid cartilage. The inferior parathyroid glands are near the bottom of each thyroid lobe.

Parathyroid anatomy is unpredictable. Although having four parathyroid glands is common, the number can vary from two to six or even more. Even the location of the glands is variable. Although they’re usually located behind the thyroid, they can be in the lower regions of the neck and even the thorax.

Parathyroid glands produce parathyroid hormone that stimulates the breaking down of bone to increase calcium levels in the blood. It also helps you absorb more calcium from the foods you eat.

The parathyroid arteries typically branch from the inferior thyroid artery. However, the superior parathyroid glands may also be supplied by branches of the superior thyroid artery. The parathyroid veins drain into the thyroid veins. Lymph flows to the deep cervical and paratracheal nodes.

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