ABSTRACT
Each thyroid lobe is supplied by arterial blood from primary sources. A superior thyroid artery, arising principally from the external carotid artery, supplies blood to the rostral area of the thyroid lobe. Evaluation of the thyroid microcirculation or of blood flow in thyroid arteries has a number of potentially valuable clinical applications. The venous efflux from the thyroid drains into bilateral superior, middle, or inferior thyroid veins. One of the most striking features of the vascular anatomy of the thyroid gland is the complex network of blood capillaries that encapsulate each follicle. As for any organ, the blood flow to the thyroid provides oxygen and energy sources necessary to support the ongoing activity of cells within the gland. Thyroxine and triiodothyronine are hormones synthesized by follicular cells within the thyroid. Under normal conditions, thyroid blood flow appears to be relatively labile. Electromagnetic blood flowmetry is a technique that has been used to index thyroid artery blood flow in humans.
