Thyroid ima artery

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Thyroid ima artery
Source Brachiocephalic, others
Supplies Thyroid gland, trachea, parathyroid glands, thymus gland (as thymica accessoria)
Latin Arteria thyroidea ima
TA A12.2.04.005
FMA 3936
Anatomical terminology

The thyroid ima artery (thyroidea ima artery, arteria thyroidea ima, thyroid artery of Neubauer or the lowest thyroid artery) is an artery of the head and neck. It is an anatomical variant that, when present, supplies blood to the thyroid gland primarily, or the trachea, the parathyroid gland and the thymus gland (as thymica accessoria) in rare cases. It has also been reported to be a compensatory artery when one or both of the inferior thyroid arteries are absent and in a few cases the only source of blood to the thyroid gland. It varies in origin, size, blood supply, and termination, and occurs in only 3–10% of the population. Because of the variations and rarity, it may lead to surgical complications.

Human variability, or human variation, is the range of possible values for any characteristic, physical or mental, of human beings.

Trachea cartilaginous tube that connects the pharynx and larynx to the lungs

The trachea, colloquially called the windpipe, is a cartilaginous tube that connects the pharynx and larynx to the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from the larynx and branches into the two primary bronchi. At the top of the trachea the cricoid cartilage attaches it to the larynx. This is the only complete tracheal ring, the others being incomplete rings of reinforcing cartilage. The trachealis muscle joins the ends of the rings and these are joined vertically by bands of fibrous connective tissue – the annular ligaments of trachea. The epiglottis closes the opening to the larynx during swallowing.

Parathyroid gland endocrine gland

Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes parathyroid hormone in response to a low blood calcium, which plays a key role in regulating the amount of calcium in the blood and within the bones.



The veins of the thyroid gland (thyroid ima artery not labeled, but region of origin and route are visible) Gray560.png
The veins of the thyroid gland (thyroid ima artery not labeled, but region of origin and route are visible)

The thyroid ima artery is an embryonic artery and it occurs because of the failure of the vessel to close, remaining patent (open). [1]

Fetal circulation

In animals that give live birth, the fetal circulation is the circulatory system of a fetus. The term usually encompasses the entire fetoplacental circulation, which includes the umbilical cord and the blood vessels within the placenta that carry fetal blood.

The artery has a variable origin. It mostly arises from the brachiocephalic trunk, [2] but may also originate from the aortic arch, the right common carotid, the subclavian, the pericardiacophrenic artery, the thyrocervical trunk, the transverse scapular or the internal thoracic artery. [3] It ascends in front of the trachea in the superior mediastinum to the lower part of the thyroid gland. [1]

Aortic arch part of the aorta between the ascending and descending aorta

The aortic arch, arch of the aorta, or transverse aortic arch is the part of the aorta between the ascending and descending aorta. The arch travels backward, so that it ultimately runs to the left of the trachea.

Subclavian artery major arteries of the upper thorax, below the clavicle

In human anatomy, the subclavian arteries are paired major arteries of the upper thorax, below the clavicle. They receive blood from the aortic arch. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax. On the left side of the body, the subclavian comes directly off the aortic arch, while on the right side it arises from the relatively short brachiocephalic artery when it bifurcates into the subclavian and the right common carotid artery.

Pericardiacophrenic artery

The pericardiacophrenic artery is a long slender branch of the internal thoracic artery. It accompanies the phrenic nerve, between the pleura and pericardium, to the diaphragm, to which it is distributed. It anastomoses with the musculophrenic and superior phrenic arteries.

It differs in size and ranges from as small as accessory thyroid arteries to the size of primary thyroid vessels. The diameter of the lumen of the artery ranges from 3–5 millimetres (0.12–0.20 in). [4] The artery may be present as an accessory thyroid artery but sometimes appears to compensate for incompetence or absence of one or more main thyroid vessels. [5] Since it begins from below the thyroid gland and ascends upwards, it is mostly associated with absence or reduced size of the inferior thyroid arteries. [6] In such cases, it is known as the accessory inferior thyroid artery. [4] [5] In rare cases, the artery has been seen to be compensating for absence of one or both superior thyroid arteries. [7]

Lumen (anatomy) cavity within an organ

In biology, a lumen is the inside space of a tubular structure, such as an artery or intestine. It comes from Latin lumen, meaning 'an opening'.

In cases where the length of the thyroid ima artery is shorter, the artery ends by supplying the thymus gland and is known as thymica accessoria. [4]


When present, the thyroid ima's chief supply is the thyroid gland, though it also supplies the trachea. The artery may extend and supply the parathyroid glands. An infrequently observed artery, it is more frequently reported in the context of enlarged parathyroid glands (parathyroid adenomas). The artery ends by supplying the thyroid gland, or the parathyroid glands, as a single unit or as multiple branches. [5] [8] The artery is also found to be the only supply of the parathyroid gland in rare cases. [5]

Parathyroid adenoma Human disease

A parathyroid adenoma is a benign tumor of the parathyroid gland. It generally causes hyperparathyroidism; there are very few reports of parathyroid adenomas that were not associated with hyperparathyroidism.

Clinical significance

The artery is only present in approximately 3–10% of the population. [9] [10] Thyroid ima artery is of surgical importance; due to its relatively small size and infrequent presence it can cause complications such as severe bleeding in surgery of the thorax, trachea, thyroid or parathyroid glands. [11] Knowledge of occurrence of the artery is especially important during tracheostomy and thyroidectomy. [4] Because the artery is smaller than the other thyroid vessels, and having an origin from one of the bigger vessels, a brisk cut while performing the surgery may cause complications such as severe hemorrhage and significant blood loss. [11] [12] The artery, if dissected, may draw back into the mediastinum and further complicate the condition by causing hemorrhage and clots in the thoracic cavity. [13]


The thyroid ima artery was first defined by German anatomist Johann E. Neubauer in the year 1772. Hence, it was named the thyroid artery of Neubauer. [14] The artery originates lower than the inferior thyroid arteries, so it is also known as the lowest thyroid artery. [9] [10]

Arteria thyroidea ima is the Latin name of the artery. [10] [2]

Other animals

The presence of thyroid ima artery is also observed in other higher primates. The artery has been reported in gorillas, gibbons, macaques and gray langurs. Variations in the origin were also seen; it was found to originate from the aorta in the thorax, or the carotid in the neck. [15]

Related Research Articles

Neck part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk

The neck is the part of the body, on many vertebrates, that separates the head from the torso. It contains blood vessels and nerves that supply structures in the head to the body. These in humans include part of the esophagus, the larynx, trachea, and thyroid gland, major blood vessels including the carotid arteries and jugular veins, and the top part of the spinal cord.

Brachiocephalic artery aorta descendens

The brachiocephalic artery is an artery of the mediastinum that supplies blood to the right arm and the head and neck.

Thoracic duct

In human anatomy, the thoracic duct is the larger of the two lymph ducts of the lymphatic system. It is also known as the left lymphatic duct, alimentary duct, chyliferous duct, and Van Hoorne's canal. The other duct is the right lymphatic duct. The thoracic duct carries chyle, a liquid containing both lymph and emulsified fats, rather than pure lymph. Thus when it ruptures, the resulting flood of liquid into the pleural cavity is known as chylothorax.

Internal jugular vein paired vein collecting the blood from the brain, the superficial parts of the face, and the neck

The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. The vein runs in the carotid sheath with the common carotid artery and vagus nerve.

Recurrent laryngeal nerve Nerve in the human body

The recurrent laryngeal nerve (RLN) is a branch of the vagus nerve that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. There are two recurrent laryngeal nerves, right and left, in the human body. The right and left nerves are not symmetrical, with the left nerve looping under the aortic arch, and the right nerve looping under the right subclavian artery then traveling upwards. They both travel alongside of the trachea. Additionally, the nerves are one of few nerves that follow a recurrent course, moving in the opposite direction to the nerve they branch from, a fact from which they gain their name.

Common carotid artery One of the two arteries that supply the head and neck with blood

In anatomy, the left and right common carotid arteries (carotids) are arteries that supply the head and neck with oxygenated blood; they divide in the neck to form the external and internal carotid arteries.

Thoracic inlet

The thoracic inlet, also known as the superior thoracic aperture, refers to the opening at the top of the thoracic cavity. It is also clinically referred to as the thoracic outlet, in the case of thoracic outlet syndrome; this refers to the superior thoracic aperture, and not to the lower, larger opening, the inferior thoracic aperture.

Superior thyroid artery

The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland.

Aberrant subclavian artery

Aberrant subclavian artery, or aberrant subclavian artery syndrome, is a rare anatomical variant of the origin of the right or left subclavian artery. This abnormality is the most common congenital vascular anomaly of the aortic arch, occurring in approximately 1% of individuals.

Thyrocervical trunk Artery of the neck

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.

Transverse cervical artery Artery of the neck

The transverse cervical artery is an artery in the neck and a branch of the thyrocervical trunk, running at a higher level than the suprascapular artery.

Inferior thyroid artery Artery of the neck

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.

Superior laryngeal nerve

The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the inferior ganglion of vagus nerve and in its course receives a branch from the superior cervical ganglion of the sympathetic nervous system.

Head and neck anatomy

This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat.

Prevertebral fascia

The prevertebral fascia is a fascia in the neck.

Pretracheal fascia

The pretracheal fascia is a portion of the structure of the human neck. It extends medially in front of the carotid vessels and assists in forming the carotid sheath.

Tracheoinnominate fistula

Tracheoinnominate fistula is an abnormal connection (fistula) between the innominate artery and the trachea. A TIF is a rare but life-threatening iatrogenic injury, usually the sequela of a tracheotomy.

In CT scan of the thyroid, focal and diffuse thyroid abnormalities are commonly encountered. These findings can often lead to a diagnostic dilemma, as the CT reflects the nonspecific appearances. Ultrasound (US) examination has a superior spatial resolution and is considered the modality of choice for thyroid evaluation. Nevertheless, CT detects incidental thyroid nodules (ITNs) and plays an important role in the evaluation of thyroid cancer.


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