| External carotid artery | |
|---|---|
 The external carotid artery arises from thecommon carotid artery and supplies structures in the face and neck. | |
| Details | |
| Precursor | 1 and 2.aortic arches |
| Source | Common carotid artery |
| Branches | Superior thyroid,lingual,facial,ascending pharyngeal,occipital,posterior auricular,maxillary,superficial temporal |
| Identifiers | |
| Latin | arteria carotis externa |
| MeSH | D002342 |
| TA98 | A12.2.05.001 |
| TA2 | 4369 |
| FMA | 10635 |
| Anatomical terminology | |
Theexternal carotid artery is the majorartery of the head and upper neck. It arises from thecommon carotid artery. It terminates by splitting into thesuperficial temporal andmaxillary artery within theparotid gland.[1]
The external carotid artery arises from thecommon carotid artery just inferior to the upper border of thethyroid cartilage.[1]
At its origin, this artery is closer to the skin and more medial than the internal carotid, and is situated within thecarotid triangle.
It curves to pass anterosuperiorly before inclining posterior-ward to reach the space posterior the neck of themandible, where it divides into thesuperficial temporal andmaxillary artery within theparotid gland.
It rapidly diminishes in size as it travels up the neck, owing to the number and large size of its branches.
At the origin, external carotid artery is more medial thaninternal carotid artery. When external carotid artery ascends the neck, it lies more lateral than internal carotid artery.[2]
The external carotid artery is covered by the skin, superficial fascia,platysma muscle, deep fascia, and anterior margin of thesternocleidomastoid; it is crossed by thehypoglossal nerve, by thelingual,ranine,common facial, andsuperior thyroid veins; and by thedigastricus andstylohyoideus muscles; higher up it passes deeply into the substance of theparotid gland, where it lies deep to thefacial nerve and the junction of the temporal and internal maxillary veins.
Medial to it are thehyoid bone, the wall of thepharynx, thesuperior laryngeal nerve, and a portion of theparotid gland.
Posterior to it, near its origin, is thesuperior laryngeal nerve; and higher up, it is separated from theinternal carotid by thestyloglossus andstylopharyngeus muscles, theglossopharyngeal nerve, the pharyngeal branch of thevagus, and part of the parotid gland.
As the artery travels upwards, it gives the following branches:
The external carotid artery terminates as two branches:
The superior thyroid artery anastomoses withinferior thyroid artery, where the latter arises fromthyrocervical trunk of thesubclavian artery.[2]
Terminal branch of facial artery anastomose withophthalmic artery ofinternal carotid artery.[2]
Posterior auricular artery anastomose with occipital artery, another branch of external carotid artery.[2]
One of the branches of superficial temporal artery anastomose with lacrimal and palpebral branches of ophthalmic artery.[2]
In children, the external carotid artery is smaller than theinternal carotid; but in the adult, the two vessels are of nearly equal size.
The condition and health of the external carotid arteries is usually evaluated usingDoppler ultrasound,CT angiogram orphase 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).[4]
PSV values greater than 200 cm/s are considered to be predictive of more than 50% of externalcarotid artery stenosis.[5]
