where does the inferior thyroid artery come from

Where is the thyroid artery located?

The inferior thyroid artery (Fig. 22.7) arises from the thyrocervical trunk, which branches from the subclavian artery on the pleural dome, in front and a little lateral of the vertebral artery. Fig. 22.7. Superior and inferior thyroid arteries. A vertical part beginning just outside the vertebral artery.

What is the difference between the superior and inferior thyroid artery?

Superior thyroid artery – arises as the first branch of the external carotid artery. It lies in close proximity to the external branch of the superior laryngeal nerve (innervates the larynx). Inferior thyroid artery – arises from the thyrocervical trunk (a branch of the subclavian artery).

What branches of the inferior thyroid artery supply the pharynx?

The pharyngeal branches of the inferior thyroid artery supply the pharynx . The glandular branches of the inferior thyroid artery are small branches which directly supply the thyroid gland .

What is the blood supply to the thyroid gland?

Blood supply to the thyroid gland is achieved by two main arteries; the superior and inferior thyroid arteries. These are paired arteries arising on both the left and right. The superior thyroid artery is the first branch of the external carotid artery.

Where do thyroid arteries come from?

This endocrine gland has a highly vascular blood supply due to its physiologic significance. The superior thyroid artery (STA) arising from the external carotid artery (ECA), and the inferior thyroid artery (ITA) branching from the thyrocervical trunk create the blood supply to the thyroid gland.

Where does the inferior laryngeal artery come from?

The inferior laryngeal artery arises from the inferior thyroid artery, itself a branch of the thyrocervical trunk. This artery travels along the same course as the RLN.

What does the inferior thyroid vein come off of?

The inferior thyroid vein arises from an anastomotic venous network between the superior and middle thyroid veins.

Which artery supplies the inferior thyroid artery?

Origin. The inferior thyroid artery (Fig. 22.7) arises from the thyrocervical trunk, which branches from the subclavian artery on the pleural dome, in front and a little lateral of the vertebral artery.

Why the inferior thyroid artery should be ligated away from the gland during operation on it?

Because of extreme variability of the inferior thyroid artery and the RLN, it is suggested that the artery be ligated either proximally or at its tertiary branches on thyroid capsule. The internal branch of the SLN is not potentially at risk during thyroidectomy unless the superior thyroid artery is ligated proximally.

How many inferior thyroid veins are there?

Anatomical Parts The inferior thyroid veins appear two, frequently three or four, in number, and arise in the venous plexus on the thyroid gland, communicating with the middle and superior thyroid veins.

Which arteries mainly supply the thyroid gland?

The superior thyroid artery (STA) arising from the external carotid artery (ECA), and the inferior thyroid artery (ITA) branching from the thyrocervical trunk create the blood supply to the thyroid gland.

Does massaging your thyroid help?

Increasing blood flow through massage has a great effect on the thyroid via the lymphatic system which flows to all endocrine organs. Another benefit of massage on thyroid is reduced stress levels which in turn reduces cortisol which also has another extra benefit of helping to manage weight.

Where is the thyrocervical trunk located?

The thyrocervical trunk is a branch of the subclavian artery arising from the first portion of this vessel, i.e. between the origin of the subclavian artery and the inner border of the scalenus anterior muscle. It is located distally to the vertebral artery and proximally to the costocervical trunk.

What does the Arteria Thyroidea superior supply?

The superior thyroid artery is a branch of the external carotid artery and supplies the larynx and thyroid gland.

Where is the recurrent laryngeal nerve?

The recurrent laryngeal nerve (RLN) branches off the vagus nerve (cranial nerve X) and has an indirect course through the neck. It supplies innervation to all of the intrinsic muscles of the larynx, except for the cricothyroid muscles, as well as sensation to the larynx below the level of the vocal cords.

What is a result of injury to the superior laryngeal nerve?

Damage to the laryngeal nerve can result in loss of voice or obstruction to breathing. Laryngeal nerve damage can be caused by injury, tumors, surgery, or infection. Damage to the nerves of the larynx can cause hoarseness, difficulty in swallowing or breathing, or the loss of voice.

Where is the inferior thyroid artery located?

The inferior thyroid artery is an artery in the neck. It arises from the thyrocervical trunk and passes upward, in front of the vertebral artery and longus colli muscle. It then turns medially behind the carotid sheath and its contents, and also behind the sympathetic trunk, the middle cervical ganglion resting upon the vessel.

What are the branches of the inferior thyroid artery?

The branches of the inferior thyroid artery are the inferior laryngeal, the oesophageal, the tracheal, the ascending cervical and the pharyngeal arteries.

What is the injection of dye into the inferior thyroid artery used for?

The injection of dye into the inferior thyroid artery can be used as an alternate method in identification the recurrent laryngeal nerve.

Which branch of the inferior thyroid artery supplies the pharynx?

The pharyngeal branches of the inferior thyroid artery supply the pharynx .

Which artery supplies the esophagus?

The esophageal branches of the inferior thyroid artery supply the esophagus, and anastomose with the esophageal branches of the aorta .

Is the laryngeal nerve in front of the thyroid artery?

The recurrent laryngeal nerve passes upward generally behind, but occasionally in front of, the inferior thyroid artery . This makes it vulnerable to injury during surgery that involves ligating the inferior thyroid artery, such as excision of the lower pole of the thyroid gland. Also as the parathyroid is mainly supplied by inferior thyroid artery accidental ligation during thyroidectomy can cause hypoparathyroidism.

Why is the distal inferior thyroid artery taken?

The artery is taken directly on the thyroid capsule to reduce the risk of parathyroid ischemia. The superior parathyroid glands are more constant in position and are more frequently seen at thyroidectomy for goiter; therefore they are more readily preserved. In their series of 80 substernal goiters, Katlic, Grillo, and Wang noted that upper glands were seen twice as often as lower glands.11 The inferior parathyroid gland is more widely distributed and more likely to be significantly displaced by inferior pole goitrous change. Therefore our real emphasis during goiter surgery should be on superior parathyroid preservation. Inferiorly, we must strictly adhere to capsular dissection so as to preserve displaced inferior parathyroid glands. It is important to emphasize that with goiter surgery, as with all thyroid surgery, any resected thyroid specimen must be meticulously examined for capsular parathyroid glands before being sent to pathology. Any capsular parathyroid glands that are found should be dissected off, biopsied to confirm parathyroid tissue, and then autotransplanted. These glands may be found within folds and crevices of the goiter surface.

Which artery supplies the inferior parathyroid gland?

Parathyroid Vascular Anatomy. The inferior thyroid artery supplies the inferior parathyroid gland. Delattre found that the inferior thyroid artery is absent, more commonly on the left, in approximately 10% of patients.

What is the thyroid gland supplied by?

The thyroid gland is supplied by the superior and inferior thyroid arteries ( Fig. 2.4). The arteries are large in size. Their branches often anastomose on the gland and inside it, ipsilaterally and contralaterally. The superior thyroid artery is closely related to the superior laryngeal nerve’s external branch.

What is the ascending cervical artery?

The ascending cervical artery is a small branch that arises as the inferior thyroid turns medially behind the carotid sheath. It supplies the adjacent muscles and gives off spinal branches to supply vertebral bodies and the spinal cord, owing to its anastomoses with the spinal arteries.

What are the terminal branches of the thyroid?

It divides into three terminal branches: 1. A posterior branch forms an anastomosis with the posterior branch of the superior thyroid artery, along the posterior medial border of the thyroid lobe.

Which artery passes anterior to the vertebral artery and posterior to the carotid sheath?

At the level of C5, the inferior thyroid artery passes anterior to the vertebral artery and posterior to the carotid sheath. Manipulation of the inferior thyroid artery at its origin affects the homolateral vertebral artery.

Where does the parathyroid artery supply blood?

The superior parathyroid gland is usually vascularized by the inferior thyroid artery or by an anastomotic branch between the inferior thyroid and the superior thyroid artery. Several studies have described that in 20% to 45% of cases, the superior parathyroid gland derives significant blood supply from the superior thyroid artery. Usually, such blood supply is derived from a posterior branch of the superior thyroid artery and is given off at the level of the superior pole of the thyroid. 72 Care is required in dissecting this superior pole to preserve the posterior branch of the superior thyroid artery. The small vessels that bridge the interval between the medial surface of the parathyroid gland and the lateral surface of the thyroid are generally insufficient to vascularize the parathyroid gland.

Which artery supplies the inferior third of the thyroid gland?

The inferior thyroid artery supplies the inferior third of the thyroid gland.

What are the terminal branches of the thyroid?

It divides into three terminal branches: 1. A posterior branch forms an anastomosis with the posterior branch of the superior thyroid artery, along the posterior medial border of the thyroid lobe.

What is the esophageal arterial system?

The esophageal arterial blood supply arises from multiple vessels, which anastamose within the submucosa, forming extensive networks. The superior and inferior thyroid arteries supply the upper esophagus. The descending aorta and bronchial and right intercostal arteries supply the midesophagus, and the left gastric, left inferior phrenic, and splenic arteries supply the distal esophagus. The venous drainage is executed by a network of vessels within the esophageal wall (Fig. 5). Small intraepithelial vessels drain from the stratified epithelium of the mucosa into the superficial venous plexus within the two deeper layers, the lamina propria and muscularis mucosae. From the superficial plexus, blood is drained into the deep intrinsic veins located within the submucosa. Perforating veins traverse laterally through the muscularis propria to connect the deep intrinsic veins to the adventitial extrinsic venous drainage system, which is composed of the serosal and periesophageal veins. Thereafter, drainage is variable, depending on the location. The upper esophagus drains to the superior vena cava, the midesophagus drains to the azygous veins, and the distal esophagus drains to the portal vein. Portal hypertension leads to dilation of the deep intrinsic veins, eventually displacing more superficial structures and protruding into the esophageal lumen. The lymphatic system is also segmental, with extensive submucosal anastomoses that account for the distant spread of most esophageal cancers.

How to locate parathyroid gland?

Identify the thyroid gland. Tracing the superior and inferior thyroid arteries to their small branches may help locate the parathyroid glands. At this time, place a clamp across the esophagus at a level even with the carina to prevent loss of gastric contents ( Fig. 4-29 ). Transect the esophagus just superior to the clamp. Remove the neck organs (larynx, thyroid, trachea, upper esophagus) as a block by transecting the thyrohyoid membrane and cutting any posterior connections ( Fig. 4-30 ). If required, include the tongue in continuity with the other neck structures.

How does the thyroid work?

The thyroid gland has a rich blood supply from the external carotid and subclavian arteries via the superior and inferior thyroid arteries ( Fig. 7.1 ). The rate of blood flow through the gland is controlled by both sympathetic and parasympathetic nerves. The normal rate of blood flow through the thyroid is around twice that of the kidney (at 3 mL/min/g or 30–60 mL/min through the gland), but in disorders involving growth of the thyroid tissue, such as diffuse toxic goitre, may reach 1 L/min in total. This can be detected with a stethoscope: there is an audible bruit over the gland.

What is the ligament of Berry?

The most difficult part of the dissection during a thy roidectomy usually involves the ligament of Berry. The ligament is situated at the posterior lateral portion to the thyroid gland just caudal to the cricoid cartilage. A small branch of the inferior thyroid artery traverses the ligament, as do one or more veins from the thyroid gland. These vessels are usually readily identified and ligated. Should bleeding occur, it should be controlled by pressure with no clamping until the RLN is identified. A small amount of persistent bleeding at the end of the case can be controlled with the placement of a small pledget of thrombin-soaked gel foam. A tubercle of Zuckerkandl may extend over the RLN at the ligament of Berry. In addition to having a consistent relationship with the location of the RLN, the upper parathyroid gland may be situated at the tip of this protruding portion of thyroid tissue.

What is the arterial supply to the small and large intestine?

The arterial supply of blood to the small and large intestine is from the celiac artery, superior mesenteric artery (SMA), and inferior mesenteric artery (IMA). Collateral vessels, which vary from person to person, may include the meandering mesenteric artery or arc of Riolan at the base of the mesentery (connecting the SMA and IMA), the marginal artery of Drummond along the mesenteric border (connecting the SMA and IMA), the pancreaticoduodenal arcade (connecting the celiac artery and SMA), the arc of Barkow (connecting the celiac artery and SMA), and the arc of Buhler (connecting the celiac artery and SMA). These collaterals can rapidly enlarge in response to localized mesenteric ischemia. During states of low arterial flow, such as in patients with low systemic arterial blood pressure, “watershed” areas such as the splenic flexure, which is farthest away from arterial flow, are more likely to be involved. In contrast, when a major arterial vessel such as the IMA is suddenly occluded, the splenic flexure is less likely to be involved because of collaterals from the SMA circulation.

Where does the superior thyroid originate?

According to classical anatomical textbooks, the superior thyroid artery originates from the external carotid artery. However, certain noteworthy anatomical variations have been noted in the origin of this vessel. This artery arises from the external carotid artery in 35% of the cases, from the bifurcation of the common carotid artery in another ...

How many branches does the superior thyroid artery have?

The superior thyroid artery has five branches; The glandular branches, which supply the upper half of the thyroid gland. They can be individually defined as the anterior, posterior and lateral branches, and anastomose with those of the inferior thyroid artery to complete the vascular network that feeds the whole gland.

How long does it take to read a thyroid artery?

Reading time: 3 minutes. Superior thyroid artery (Arteria thyroidea superior) The superior thyroid artery is the first branch of the external carotid artery that supplies the thyroid gland, cricothyroid and infrahyoid muscles, a part of the sternocleidomastoid muscle and the upper larynx.

Which artery supplies the upper part of the larynx?

The superior laryngeal artery supplies the structures of the upper part of the larynx. It anastomoses with the inferior laryngeal artery (from the inferior thyroid artery) to complete the vascular network of the larynx. The cricothyroid branch supplies the cricothyroid muscle.

Which artery gives off five branches that contribute to the blood supply of the muscles and the viscera of the neck?

The superior thyroid artery gives off five branches that contribute to the blood supply of the muscles and the viscera of the neck.

Where does the external laryngeal nerve go?

The external laryngeal nerve lies posteromedial to the superior thyroid artery, being prone to ligation during surgical procedures on the gland.

Where is the inferior thyroid artery located?

Inferior thyroid artery – arises from the thyrocervical trunk (a branch of the subclavian artery). It lies in close proximity to the recurrent laryngeal nerve (innervates the larynx).

What is the arterial supply to the thyroid gland?

Arterial Supply. The arterial supply to the thyroid gland is via two main arteries: Superior thyroid artery – arises as the first branch of the external carotid artery. It lies in close proximity to the external branch of the superior laryngeal nerve (innervates the larynx).

What happens when the thyroid gland descends?

The descent of the developing thyroid gland forms the thyroglossal duct – an epithelialised tract that connects the gland to its origin at the foramen cecum. It usually regresses by the 10th week of gestation, but can persist in some individuals. If it fails to regress, the duct can give rise to cysts or fistulae.

What are the structures of the thyroid gland?

The thyroid gland is closely associated with numerous other structures in the anterior neck: 1 Anteriorly – infrahyoid muscles, namely the sternothyroid, superior belly of the omohyoid and sternohyoid 2 Laterally – carotid sheath, containing the common carotid artey, internal jugular vein and vagus nerve 3 Medially –#N#Organs – larynx, pharynx, trachea and oesophagus#N#Nervea – external laryngeal and recurrent laryngeal

Which gland is wrapped around the cricoid cartilage?

Fig 2 – The thyroid gland consists of two lobes connected by a central isthmus. It is wrapped around the cricoid cartilage and trachea anteriorly.

Which gland is closely associated with numerous other structures in the anterior neck?

The thyroid gland is closely associated with numerous other structures in the anterior neck:

Where is the thyroid gland innervated?

The thyroid gland is innervated by branches derived from the sympathetic trunk.

Overview

Structure

Clinical significance

Additional images

See also

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