External carotid artery

Location and topography of the vessel

At its very origin, the external carotid artery lies somewhat medial to the internal carotid artery. However, as it ascends, it crosses it and comes to lie anteriorly.

Externally, the artery is securely covered by soft tissues: the platysma and the superficial layer of the cervical fascia are located superficial to it. Laterally (on the outer side of the vessel), the parotid gland (glandula parotis) is adjacent to the artery.

Four major groups of branches arise from the main trunk, providing vascularization to various regions: the anterior, posterior, medial, and terminal groups.

Anterior group of branches

This group heads toward the organs of the anterior neck region, the face, and the tongue. It includes three main vessels:

1. Superior thyroid artery (a. thyroidea superior). It originates at the very base of the external carotid artery, descending anteriorly toward the upper pole of the thyroid gland.

Its main branches:

• rr. glandulares anterior, posterior, lateralis — run to the lobes of the thyroid gland. They form important anastomoses with the inferior thyroid artery (which arises from the thyrocervical trunk).
• r. infrahyoideus — supplies the infrahyoid muscles.
• r. sternocleidomastoideus — runs to the sternocleidomastoid muscle of the same name.
• a. laryngea superior — pierces the thyrohyoid membrane (membrana thyrohyoidea) and supplies the tissues of the larynx.

1. Lingual artery (a. lingualis). It arises somewhat superior to the superior thyroid artery. Sometimes it originates as a common trunk with the facial artery — this formation is called the linguofacial trunk (truncus linguofacialis). The artery lies above the greater horn of the hyoid bone and runs anteriorly and medially.

Branches:

• r. suprahyoideus — to the suprahyoid muscles.
• r. dorsales linguae — supply the palatine tonsil and the dorsum of the tongue.
• a. sublingualis — supplies the gingiva and the sublingual salivary gland.
• a. profunda linguae — is the terminal branch, running within the thickness of the tongue to its apex and forming an anastomosis with the corresponding artery of the opposite side.

1. Facial artery (a. facialis). It arises superior to the lingual artery. Its course runs under the stylohyoid muscle and the posterior belly of the digastric muscle (m. digastricus). Then the vessel enters the submandibular fossa directly through the substance of the submandibular salivary gland. Having looped around the inferior border of the mandible, the artery emerges onto the face, where it supplies the tissues from the angle of the mouth up to the medial angle of the eye.

Its main branches: ascending palatine artery (a. palatina ascendens), submental artery (a. submentalis), superior and inferior labial arteries (aa. labiales superior et inferior), and angular artery (a. angularis).

Posterior group of branches

The vessels of this group run posteriorly, supplying the occiput and the auricle region:

• Occipital artery (a. occipitalis). It arises at the level of the posterior belly of m. digastricus and runs beneath the suboccipital muscles. It gives off branches to the sternocleidomastoid muscle (rr. sternocleidomastoidei), to the posterior surface of the auricle (r. auricularis), and to the dura mater (via the mastoid emissary vein — r. mastoideus, and via the parietal emissary vein — r. meningeus). The terminal branches (rr. occipitales) supply the skin and muscles of the occipital region.
• Posterior auricular artery (a. auricularis posterior). A small artery arising superior to the occipital artery (or by a common trunk with it). It ascends toward the mastoid process along the posterior margin of the auricle. It gives off the stylomastoid artery (a. stylomastoidea), auricular branch (r. auricularis), and occipital branch (r. occipitalis).

Medial group of branches

This group is represented by a deep branch — ascending pharyngeal artery (a. pharyngea ascendens). It arises directly from the medial wall of the external carotid artery and ascends along the lateral wall of the pharynx.

Its branches supply the pharynx (rr. pharyngeales), the dura mater (a. meningea posterior), and the tympanic cavity (a. tympanica inferior).

Note: The terminal branches of the external carotid artery form a separate independent group that requires a detailed study of the topography of the face and temporal region.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Topography and complete list of terminal branches of the external carotid artery.
• Anastomoses between the systems of the external and internal carotid arteries on the face.
• Specific features of arterial passage through skull foramina to the dura mater.
• Variant anatomy: linguofacial trunk and its clinical significance.
• Blood supply to the thyroid gland and larynx: surgical anatomy.

Other topics in the "Angiology" section

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