General characteristics of the external carotid artery
Arteria carotis externa is one of the two terminal branches of the common carotid artery (arteria carotis communis), formed at the bifurcation level at the superior border of the thyroid cartilage. Unlike the internal carotid artery, which enters the cranial cavity to supply the brain, the external carotid artery supplies the soft tissues of the face and neck, oral cavity structures, thyroid gland, and salivary glands.
The branches of the external carotid artery are traditionally divided into four groups: anterior, posterior, medial, and terminal. The anterior branches include three arteries: superior thyroid, lingual, and facial. During an oral examination in angiology, it is essential to name both the branches themselves and the areas they supply.
Superior thyroid artery
Arteria thyroidea superior is the first anterior branch, originating near the bifurcation of the common carotid artery. It supplies the thyroid gland, larynx, hyoid bone, and adjacent muscles. It gives off the following branches:
- Glandular branches (rami glandulares anteriores et posteriores) — travel to the thyroid gland.
- Cricothyroid branch (ramus cricothyroideus) — supplies the muscle of the same name.
- Sternocleidomastoid branch — supplies the musculus sternocleidomastoideus.
- Superior laryngeal artery (arteria laryngea superior) — supplies the mucosa and muscles of the larynx above the vocal cords.
- Infrahyoid branch (ramus infrahyoideus) — supplies the hyoid bone and infrahyoid muscles.
Lingual artery
Arteria lingualis branches off from the external carotid artery at the level of the greater horn of the hyoid bone and runs toward the tongue, passing deep to the hyoglossus muscle. It is the main source of blood supply to the tongue and the floor of the oral cavity. Branches of the lingual artery:
- Deep artery of the tongue (arteria profunda linguae) — the terminal branch running within the substance of the tongue to its apex.
- Dorsal branches of the tongue (rami dorsales linguae) — supply the dorsum of the tongue and the palatine tonsil.
- Suprahyoid branch (ramus suprahyoideus) — supplies the muscles superior to the hyoid bone.
- Sublingual artery (arteria sublingualis) — supplies the sublingual salivary gland, mucosa of the oral floor, and mandibular gingiva.
Facial artery
Arteria facialis arises superior to the lingual artery, passes beneath the submandibular gland, hooks around the base of the mandible at the anterior border of the masseter muscle, and ascends along the face to the medial angle of the eye. Its branches are divided into cervical and facial.
- Glandular branches (rami glandulares) — to the submandibular salivary gland.
- Ascending palatine artery (arteria palatina ascendens) — supplies the soft palate and pharyngeal wall.
- Tonsillar branch (ramus tonsillaris) — the main source of blood supply to the palatine tonsil.
- Submental artery (arteria submentalis) — supplies the tissues of the mental region.
- Inferior and superior labial arteries (arteriae labiales inferior et superior) — supply the lips, forming the circumoral arterial ring.
- Angular artery (arteria angularis) — the terminal branch at the medial angle of the eye.
The angular artery anastomoses with the dorsal nasal artery (arteria dorsalis nasi), a branch of the ophthalmic artery (arteria ophthalmica) from the internal carotid system. This anastomosis provides collateral blood supply to the face during blood flow disturbances in either system and is of great clinical significance.
Variants and anomalies
The anterior branches of the external carotid artery exhibit significant anatomical variability due to angiogenesis characteristics during the embryonic period. The most common variants include:
- Origin of the superior thyroid artery at the common carotid bifurcation level, superior to it, or inferior to it (at the level of the upper third of the thyroid cartilage).
- Common trunk of the superior thyroid and lingual arteries — truncus thyrolingualis.
- Common trunk of the lingual and facial arteries — truncus linguofacialis.
- Common trunk of all three anterior branches — truncus thyrolinguofacialis.
- A rare unfavorable variant is the absence of division of the common carotid artery into external and internal branches, where they are represented by a single trunk.
Key points
- The external carotid artery (arteria carotis externa) supplies the soft tissues of the face and neck, and the anterior neck structures.
- There are three anterior branches: the superior thyroid, lingual, and facial arteries.
- The superior thyroid artery gives off glandular, cricothyroid, superior laryngeal, and infrahyoid branches.
- The lingual artery terminates as the deep artery of the tongue and gives off dorsal, suprahyoid, and sublingual branches.
- The facial artery supplies the submandibular gland, tonsil, and lips, and terminates as the angular artery.
- The anastomosis between the angular artery and the dorsal nasal artery connects the external and internal carotid systems.
- The formation of common trunks is possible: thyrolingualis, linguofacialis, thyrolinguofacialis.
- When answering an angiology question, it is mandatory to state the name of the branch, its area of blood supply, and anastomoses.