Parathyroid glands: variation in number, size and location
- MOJ Anatomy & Physiology
Heshmat SW Haroun
PDF Full Text
Parathyroid glands (PTGs) develop from the pharyngeal pouches. Their anatomy exhibits variations regarding their number and locations. Parathyroid surgery is mostly gratifying in experienced hands but sometimes failing due to the possibility of ectopic positions of the glands. Abnormal descent of the PTGs, during development, is responsible for these ectopic positions. Supernumerary PTGs are usually diseased and ectopic inside the thyroid gland, inside the thymus gland, or elsewhere in the mediastinum. In parathyroidectomies for primary and secondary hyperparathyroidism, preoperative techniques for accurate localization of the PTGs are recommended, like ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), four-dimensional computerized tomography (4DCT), aminolevulinic acid-induced fluorescence, Technetium Tc 99m sestamibi scanning (MIBI), Tc-99m RBC imaging, arteriography and selective venous sampling for parathormone. For a successful parathyroidectomy, a surgeon must be excellently aware of the anatomical variations, development and pathophysiology of the PTGs.
parathyroid glands, development, localization, number, size, hyperparathyroidism, surgeries, computerized tomography, parathyroid IV, recurrent parathyroidectomy, thyroid parenchyma, mediastinum