Content:
- What vessels supply blood to the thyroid gland?
- The structure of the upper thyroid arteries
- The structure of the lower arteries
- Fifth artery (lowest)
- Veins
The thyroid gland is the most important element of the endocrine system in the human body. Through the production of hormones, the thyroid gland regulates metabolic processes, ensures the normal functioning of the cardiovascular and nervous systems.
The thyroid gland is located in front of the trachea, on the front of the neck. It consists of two lobes and an isthmus, due to which the shape of the gland is usually compared to the outlines of the wings of a butterfly.
The thyroid gland has an abundant blood supply, greater than that of other organs. The blood flow rate in this gland for each gram of tissue is 5 ml per minute. The blood supply to the gland is provided by the vessels of the thyroid gland.
What vessels supply blood to the thyroid gland?
The blood supply to the human thyroid gland occurs through 2 pairs of arteries:
- Upper thyroid.
- Lower thyroid.
Sometimes another artery, unpaired, the lowest, takes part in the blood supply of this organ.
The structure of the upper thyroid arteries
The superior artery starts from the carotid artery, the anterior surface of its outer part. The artery goes down forward and, approaching the lobe of the gland, is divided into 2 parts (branches): anterior, posterior.
A thin posterior branch runs along the back of the lobe of the gland, supplying it with blood, and connects (anastomoses) to the posterior branch of the inferior artery. In addition, the posterior branch of the superior artery is connected to the arteries that feed the trachea, larynx, and esophagus.
The larger anterior branch passes in front and feeds the anterior part of the gland lobe, connects in the isthmus with the second superior artery (feeding the second lobe).
The location of the artery from the carotid artery and the position of the thyroid arteries may differ from person to person.
The structure of the lower arteries
The lower arteries are larger than the upper ones. Usually they start from one of the branches of the subclavian artery (thyroid-cervical trunk). The artery rises up, then forms an arc (having a bulge upward) and then goes down, approaching the posterior surface of the glandular lobe. Nutrition of the gland (mainly its posterior part) occurs due to the branching of the lower arteries into several branches.
In rare cases (about 6%), the lower arteries may not be at all, sometimes they start from the aortic arch, sometimes depart from the brachiocephalic trunk, vertebral, internal carotid or thoracic arteries. There are many options for branching the lower arteries.
Fifth artery (lowest)
10% of people have a fifth unpaired thyroid artery, which feeds mainly the isthmus of the gland. It departs most often from the aortic arch, but it can also begin from other arteries:
- Subclavian.
- Lower thyroid.
- Sleepy.
- Brachiocephalic trunk.
Veins
In addition to arteries, veins also belong to the vessels of the thyroid gland:
- Upper – accompany the upper arteries.
- Medium – runs apart.
- Lower.
- Unpaired vein.
Due to the functioning of the veins of the thyroid gland, in the area of the gland there are a large number of collaterals (branches, detours) that provide blood flow in case of damage to large vessels.
Arteries branch out and join together to form collateral systems that supply blood to the thyroid gland, for example, when ligating arteries during surgery.