The thyroid gland is an internal secretion organ located in the neck and regulates many vital processes of the human body. The veins that originate in the thyroid gland and flow into the blood supply system of the head have some specific features.
The thyroid gland is innervated, and its parasympathetic innervation is carried out by sympathetic nerves. During muscle contraction associated with the stimulating effect of the sympathetic nervous system, there is an increase in the vascular tone of the thyroid gland, a decrease in the volume of blood passing through it, which can cause some local swelling of the veins of this area.
However, the veins leading from the thyroid gland to the jugular vein have an additional factor that can cause them to swell - the veins are supplied with both arterial and venous blood. When the blood pressure level in this area increases, there is a decrease in venous pressure, leading to an increase in blood flow to the veins. This can be especially noticeable in an upright position of the body or during arousal of the body.
Analysis of these mechanisms suggests that the veins leading from the thyroid gland into the blood may require more space to compensate for the increase in blood pressure and blood volume due to active body processes. Thus, the swelling of these veins may indicate some kind of