External carotid artery

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The external carotid artery (ECA) is one of the two terminal branches of the common carotid artery. The other terminal branch is the internal carotid (ICA), which is somewhat larger than the ECA.

Summary

origin: bifurcation of thecommon carotid artery
course: under thesubmandibular gland and into theparotid gland
branches:
supply: neck, face andbase of skull
termination: division into(internal) maxillary artery andsuperficial temporal artery

Gross anatomy

Origin and course

The ECA begins at the level of the upper border of the thyroid cartilage (at the level of the fourth cervical vertebra). It takes a slightly curved course upwards and anteriorly before inclining backwards to the space behind the neck of the mandible. Along its course, it rapidly diminishes in size and as it does so, gives of various branches (see below). As it enters the parotid gland, it gives rise to its terminal branches, the superficial temporal and maxillary arteries.

Branches

The branches of the external carotid artery can be subdivided into groups:

arising from the carotid triangle

posterior auricular artery

terminal branches
- (internal) maxillary artery
- superficial temporal artery

Memorable mnemonics for these branches include:

Some Anatomists Like Freaking Out Poor Medical Students
Some Anatomists Like F-ing, Others Prefer S&M
Some American Ladies Found Our Pyramids Most Satisfactory

Relations

anteriorly (i.e. ECA is crossed by these structures)
- upper root of ansa cervicalis
- hypoglossal nerve (CN XII)
- posterior belly of digastric muscle
- stylohyoid muscle and ligament
- facial nerve (CN VII) (within the parotid gland)
passing between ECA and ICA
- pharyngeal branch of vagus nerve (CN X)
- glossopharyngeal nerve (CN IX)
- stylopharyngeus muscle
- styloglossus muscle
posteriorly (i.e. ECA lies on these structures)
- pharyngeal wall
- superior laryngeal branch of vagus nerve (CN X)
- deep lobe of the parotid gland

Variant anatomy

variations in origin arise from the anomalous bifurcation of the common carotid artery - bifurcations may commonly be seen at the level of the cricoid cartilage (C5 level) or at the hyoid bone (C2 level)
variant branching patterns
- linguofacial trunk (incidence ~20%): common origin lingual and facial arteries
- thyrolingual trunk (incidence ~2.5%): common origin superior thyroid and lingual arteries
- thyrolinguofacial trunk (incidence ~2.5%): common origin superior thyroid, lingual and facial arteries
- common occopito-auricular trunk (incidence ~12.5%): common origin occipital and posterior auricular arteries

~~-origin: <a href="/articles/carotid-bifurcation">bifurcation</a> of the <a href="/articles/common-carotid-artery-2">common carotid artery</a>~~
+origin: <a href="/articles/carotid-bifurcation">bifurcation</a> of the <a href="/articles/common-carotid-artery-2">common carotid artery</a>
~~-course: under the <a href="/articles/submandibular-gland">submandibular gland</a> and into the <a href="/articles/parotid-gland">parotid gland</a>~~
+course: under the <a href="/articles/submandibular-gland">submandibular gland</a> and into the <a href="/articles/parotid-gland">parotid gland</a>
~~-supply: <a href="/articles/neck">neck</a>, <a href="/articles/face">face</a> and <a href="/articles/base-of-skull">base of skull</a>~~
+supply: <a href="/articles/neck">neck</a>, <a href="/articles/face">face</a> and <a href="/articles/base-of-skull">base of skull</a>
~~-termination: division into <a href="/articles/maxillary-artery">(internal) maxillary artery</a> and <a href="/articles/superficial-temporal-artery">superficial temporal artery</a>~~
+termination: division into <a href="/articles/maxillary-artery">(internal) maxillary artery</a> and <a href="/articles/superficial-temporal-artery">superficial temporal artery</a>

Images Changes:

Image 1 Diagram ( create )

Image 2 Diagram ( update )

Caption was changed:

Figure 12: arteries of the neck

Position was set to .

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