The external carotid artery is the major

artery An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...

of the head and upper neck. It arises from the

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

. It terminates by splitting into the

superficial temporal In human anatomy, the superficial temporal artery is a major artery of the head. It arises from the external carotid artery when it splits into the superficial temporal artery and maxillary artery. Its pulse can be felt above the zygomatic arc ...

and

maxillary artery The maxillary artery (eg, internal maxillary artery) supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches ...

within the

parotid gland The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the m ...

Structure

Origin

The external carotid artery arises from the

just inferior to the upper border of the thyroid cartilage. At its origin, this artery is closer to the skin and more medial than the internal carotid, and is situated within the

carotid triangle The carotid triangle (or superior carotid triangle) is a portion of the anterior triangle of the neck. Anatomy Boundaries It is bounded: * Posteriorly by (the anterior border of) the sternocleidomastoid muscle, * Anteroinferiorly by (the sup ...

Course and fate

It curves to pass anterosuperiorly before inclining posterior-ward to reach the space posterior the neck of the

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

, where it divides into the

and

within the

. It rapidly diminishes in size as it travels up the neck, owing to the number and large size of its branches.

Relations

At the origin, external carotid artery is more medial than

internal carotid artery The internal carotid artery is an artery in the neck which supplies the anterior cerebral artery, anterior and middle cerebral artery, middle cerebral circulation. In human anatomy, the internal and external carotid artery, external carotid ari ...

. When external carotid artery ascends the neck, it lies more lateral than internal carotid artery. The external carotid artery is covered by the skin, superficial fascia,

platysma muscle The platysma muscle or platysma is a superficial muscle of the human neck that overlaps the sternocleidomastoid. It covers the anterior surface of the neck superficially. When it contracts, it produces a slight wrinkling of the neck, and a "bowst ...

, deep fascia, and anterior margin of the

sternocleidomastoid The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the acces ...

; it is crossed by the

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated b ...

, by the lingual,

ranine The lingual veins are veins of the tongue with two distinct courses: one group drains into the lingual vein, while another group drains either into the lingual artery, (common) facial vein, or internal jugular vein. Clinical significance The ...

common facial The facial vein usually unites with the anterior branch of the retromandibular vein to form the common facial vein, which crosses the external carotid artery and enters the internal jugular vein at a variable point below the hyoid bone. From near ...

, and

superior thyroid vein The superior thyroid vein is the vena comitans of the superior thyroid artery. It is formed by the union of deep and superficial tributaries that correspond to the arterial branches of the superior thyroid artery. Its tributaries are the . The v ...

s; and by the

digastricus The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a bilaterally paired suprahyoid muscle located under the jaw. Its posterior belly is attached to the mastoid notch of temporal bone, and its anterior belly ...

and

stylohyoideus muscles The stylohyoid muscle is one of the suprahyoid muscles. Its originates from the styloid process of the temporal bone; it inserts onto hyoid bone. It is innervated by a branch of the facial nerve. It acts draw the hyoid bone upwards and backwards. ...

; higher up it passes deeply into the substance of the

, where it lies deep to the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

and the junction of the temporal and internal maxillary veins. Medial to it are the

hyoid bone The hyoid-bone (lingual-bone or tongue-bone) () is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid-cartilage. At rest, it lies between the base of the mandible and the third cervical verte ...

, the wall of the

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

, the

superior laryngeal nerve The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the inferior ganglion of the vagus nerve and additionally receives a sympathetic branch from the superior cervical ganglion. The superior laryngeal nerve ...

, and a portion of the

. Posterior to it, near its origin, is the

; and higher up, it is separated from the

internal carotid The internal carotid artery is an artery in the neck which supplies the anterior and middle cerebral circulation. In human anatomy, the internal and external carotid arise from the common carotid artery, where it bifurcates at cervical verteb ...

by the

styloglossus The styloglossus muscle is a bilaterally paired muscle of the tongue. It originates at the styloid process of the temporal bone. It inserts onto the side of the tongue. It acts to elevate and retract the tongue. It is innervated by the hypogloss ...

and

stylopharyngeus muscle The stylopharyngeus muscle is a muscle in the head. It originates from the temporal styloid process. Some of its fibres insert onto the thyroid cartilage, while others end by intermingling with proximal structures. It is innervated by the glosso ...

s, the

glossopharyngeal nerve The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to t ...

, the pharyngeal branch of the

vagus The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fiber ...

, and part of the parotid gland.

Branches

As the artery travels upwards, it gives the following branches: * In the

: **

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. Structure From its origin under the anterior border of the sternocleidomastoid the super ...

, arising from its anterior aspect **

Ascending pharyngeal artery The ascending pharyngeal artery is an artery of the neck that supplies the pharynx. Its named branches are the inferior tympanic artery, pharyngeal artery, and posterior meningeal artery. inferior tympanic artery, and the meningeal branches (i ...

- arising from medial, or deep, aspect **

Lingual artery The lingual artery arises from the external carotid artery between the superior thyroid artery and facial artery. It can be located easily in the tongue. Structure The lingual artery first branches off from the external carotid artery. It runs ...

- arising from its anterior aspect **

Facial artery The facial artery, formerly called the external maxillary artery, is a branch of the external carotid artery that supplies blood to superficial structures of the medial regions of the face. Structure The facial artery arises in the carotid t ...

- arise from its anterior aspect **

Occipital artery The occipital artery is a branch of the external carotid artery that provides arterial supply to the back of the scalp, sternocleidomastoid muscles, and deep muscles of the back and neck. Structure Origin The occipital artery arises from (the ...

- arising from its posterior aspect **

Posterior auricular artery The posterior auricular artery is a small artery that arises from the external carotid artery. It ascends along the side of the head. It supplies several muscles of the neck and several structures of the head. Structure Origin The artery ar ...

- arising from posterior aspect The external carotid artery terminates as two branches: *

Maxillary artery The maxillary artery (eg, internal maxillary artery) supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches ...

Superficial temporal artery In human anatomy, the superficial temporal artery is a major artery of the head. It arises from the external carotid artery when it splits into the superficial temporal artery and maxillary artery. Its pulse can be felt above the zygomatic ar ...

Anastomoses

The superior thyroid artery anastomoses with

inferior thyroid artery 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 a ...

, where the latter arises from

thyrocervical trunk The thyrocervical trunks are very small arteries of the neck arising from the subclavian arteries, lateral to the vertebral arteries. They divide into branches: the inferior thyroid artery, suprascapular artery, and the transverse cervical art ...

of the

subclavian artery 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 suppli ...

. Terminal branch of facial artery anastomose with

ophthalmic artery The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some ...

. Posterior auricular artery anastomose with occipital artery, another branch of external carotid artery. One of the branches of superficial temporal artery anastomose with lacrimal and palpebral branches of ophthalmic artery.

Development

In children, the external carotid artery is smaller than the

; but in the adult, the two vessels are of nearly equal size.

Diagnostics

Left external carotid artery with normal spectral doppler

The condition and health of the external carotid arteries is usually evaluated using

Doppler ultrasound Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform imaging of the movement of tissues and body fluids (usually blood), and their relative velocity to the probe. By calculating the frequency shift of a ...

, CT angiogram or phase contrast magnetic resonance imaging (PC-MRI). Typically, blood flow velocities in the external carotid artery are measured as peak systolic velocity (PSV) and end diastolic velocity (EDV). PSV values greater than 200 cm/s are considered to be predictive of more than 50% of external

carotid artery stenosis Carotid artery stenosis is a narrowing or constriction of any part of the carotid artery, carotid arteries, usually caused by atherosclerosis. Signs and symptoms The common carotid artery is the large artery whose Common carotid artery#Clinical ...

Additional images

File:External carotid artery with branches.jpg, Branches of external carotid artery File:mra1.jpg,

Magnetic resonance angiography Magnetic resonance angiography (MRA) is a group of techniques based on magnetic resonance imaging (MRI) to image blood vessels. Magnetic resonance angiography is used to generate images of arteries (and less commonly veins) in order to evaluate ...

References

External links

* * ()
Diagram at umich.edu
{{DEFAULTSORT:External Carotid Artery Arteries of the head and neck Otorhinolaryngology