What is the anatomy of the parathyroid glands relative to thyroidectomy?

Updated: May 08, 2018
  • Author: Neerav Goyal, MD, MPH; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Answer

Answer

The parathyroid glands develop from the third and fourth pharyngeal pouches. The inferior parathyroid glands develop from the third pouch and descend at week 7 with the thymus to eventually rest at the dorsal surface of the thyroid gland outside of the thyroid capsule. The superior parathyroids develop from the fourth pouch and descend with the thyroid gland. The superior parathyroid glands are usually posterior to the inferior glands, and, as noted in the figure, they usually lie posterior to the plane of the recurrent laryngeal nerve.

Accessory parathyroid glands, as noted by Munck and Eisele, occur 3-7% and fewer than 4 glands are present in 3-6% of patients. [11] Gland descent is usually symmetric, and contralateral glands are usually located at the same level. Aberrant or ectopic glands can also be present if the glands descend incompletely or too far. Possible locations for parathyroid glands include the anterior or posterior mediastinum, carotid bifurcation, as well as the retroesophageal, retropharyngeal, or retrolaryngeal regions. The vascular supply for the parathyroid glands is usually from the inferior thyroid artery, although occasionally the superior glands are supplied by an anastomosis between the inferior and superior parathyroid arteries. [8]

Parathyroid anatomy. Parathyroid anatomy.

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