External carotid artery

Artery: External carotid artery
Arteries of the neck - right side. The external carotid artery arises from the common carotid artery - labeled Common caroti on the figure.
Plan of branches of internal maxillary artery. (External carotid labeled at bottom left.)
Latin	arteria carotis externa
Gray's	subject #144 551
Source	common carotid artery
Branches	superior thyroid, lingual, facial, ascending pharyngeal, occipital, posterior auricular, maxillary, superficial temporal
MeSH	Carotid+Artery,+External

In human anatomy, the external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it bifurcates into the external and internal carotid artery.

Course

The external carotid artery begins at the level of the upper border of thyroid cartilage, and, taking a slightly curved course, passes upward and forward, and then inclines backward to the space behind the neck of the mandible, where it divides into the superficial temporal and maxillary artery within the parotid gland.

It rapidly diminishes in size in its course up the neck, owing to the number and large size of the branches given off from it.

In the child, it is somewhat smaller than the internal carotid; but in the adult, the two vessels are of nearly equal size. At its origin, this artery is more superficial, and placed nearer the middle line than the internal carotid, and is contained within the carotid triangle.

Relations

The external carotid artery is covered by the skin, superficial fascia, Platysma, deep fascia, and anterior margin of the Sternocleidomastoideus; it is crossed by the hypoglossal nerve, by the lingual, ranine, common facial, and superior thyroid veins; and by the Digastricus and Stylohyoideus; higher up it passes deeply into the substance of the parotid gland, where it lies deep to the facial nerve and the junction of the temporal and internal maxillary veins.

Medial to it are the hyoid bone, the wall of the pharynx, the superior laryngeal nerve, and a portion of the parotid gland.

Lateral to it, in the lower part of its course, is the internal carotid artery.

Posterior to it, near its origin, is the superior laryngeal nerve; and higher up, it is separated from the internal carotid by the Styloglossus and Stylopharyngeus, the glossopharyngeal nerve, the pharyngeal branch of the vagus, and part of the parotid gland.

Branches

Branches of external carotid artery

• Arising in carotid triangle^[1]
  • Superior thyroid artery
  • Ascending pharyngeal artery
  • Lingual artery
  • Facial artery
  • Occipital artery

• Posterior auricular artery

• Terminal branches
  • Maxillary artery
  • Superficial temporal artery

Mnemonics

Mnemonics are traditionally used to commit these branches to memory.^[2] Perhaps referring to the medical school interviewing process, a commonly taught mnemonic for the external carotid branches is "Some Attendings Like Freaking Out Potential Medical Students." A similar but more memorable and vulgar mnemonic omits the minor Occipital and Posterior Auricular branches. Another is "Some Ancient Lovers Find Old Positions More Stimulating." Still another states, "Some Losers Fail Anatomy, Others Post Magnificent Scores." "Some Asian Lovers Find Old Positions More Stimulating." "Superman And Lois Fornicate On Planet Mars Sometimes" "Some Asshole Left Food On Papi's Main Staircase." "Some Angry Ladies Fight Off PMS"

Older versions

A memorable mnemonic appears in Samuel Shem’s classic novel The House of God (1978). Here Shem uses the older terms External maxillary artery for Facial artery and Internal maxillary artery for Maxillary artery. The Ascending pharyngeal and Superior thyroid appear in their correct sequence, while the names of the two terminal branches are reversed:

The internal carotid and vertebral arteries. Right side. Some of the branches labeled

Running through my mind, over and over like Muzak, was a mnemonic for the branches of the external carotid artery: As She Lay Extended Olaf’s Potato Slipped In. And even there, the only one I could remember was Olaf’s, which stood for Occipital. And what the hell use was that?

Additional images

The veins of the neck, viewed from in front.	The veins of the thyroid gland.	Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves.	Side of neck, showing chief surface markings.
Magnetic Resonance Angiography

References

1. ^ Human Anatomy - Lab 25 Step 12
2. ^ Mnemonic at medicalmnemonics.com 1799 1558 291 446

External links

• lesson5 at The Anatomy Lesson by Wesley Norman (Georgetown University)
• lesson4 at The Anatomy Lesson by Wesley Norman (Georgetown University) (infratempfossaart)
• Diagram at umich.edu