The facial artery supplies the muscles and skin of the face. It has a crucial function in maintaining these areas, and provides them with oxygen and nutrients. The facial artery is one of the eight branches of the external carotid artery. In this article we will explore the anatomy, function and clinical relevance of the vessel. We will also conclude with some review questions to test the reader’s understanding of the article content.
Course and RelationsThe common carotid artery is the first branch of brachiocephalic trunk on the right side, and the first branch of the arch of the aorta on the left side. It travels superiorly, and divides into the external and internal carotid arteries at the superior border of the thyroid cartilage. The internal carotid continues to pass upwards, and passes into the skull via the carotid canal. The artery then passes forwards to enter the cavernous sinus, and makes a 180 degrees turn back on itself and emerges lateral to the optic chiasm. The internal carotid artery then trifurcates into the middle cerebral, anterior cerebral and posterior communicating arteries, which supply various regions of the brain.
The external carotid passes upwards and superficially and gives off a number of branches to the face, and scalp. These are the superior thyroid artery (supplies the thyroid gland in the neck), the lingual artery (supplies the tongue), ascending pharyngeal artery (supplies the pharynx), facial artery (supplies the facial muscles, skin and part of the scalp), occipital artery (supplies the posterior scalp), posterior auricular artery (the scalp behind the ear as well as the ear itself), maxillary artery (the deep structures of the face) and finally the superficial temporal artery (the scalp in the temporal region). The facial artery also known as the external maxillary artery arises from the anterior surface of external carotid, and has a tortuous route along the nasolabial fold towards the medial canthus of the eye. It moves beneath the digastric and stylohyoid muscles and it will pass through the submandibular gland.
The artery will then curve over the body of the mandible (deep to platysma), as the anteroinferior angle of the masseter, will ascend forwards and upwards across the cheek, to the angle of the mouth and along the side of the nose. It terminates near the medial aspect of the eye. In the region of the head, the facial artery runs roughly parallel to the facial vein, although not adjacent to it.
Ascending Palatine Artery- This artery passed superiorly between the styloglossus and stylopharyngeus. It divides close to the levator veli palatini muscle into two branches. One branch pierces the superior pharyngeal constrictor, in order the reach the auditory tube and the palatine tonsil. It will then anastomose with the ascending pharyngeal artery as well as the tonsillar branch of the facial artery. The other branch runs with the levator veli palatini and passes over the superior pharyngeal constrictor in order to supply the soft palate, finally anastomosing with the maxillary artery (the descending palatine branch).
Tonsillar Branch- This branch ascends between styloglossus and the medial pterygoid muscle, before piercing the superior pharyngeal constrictor to reach the palatine tonsil.
Submental artery- This branch runs on the inferior aspect of the chin. This is the largest of the cervical branches of the facial artery. The branch is given off just as the facial artery passes through the submandibular gland. The vessel passes anteriorly on top of the mylohyoid muscle, beneath the digastric muscle and just inferior to the body of the mandible. The artery supplies the muscle surrounding this region, and anastomoses with the sublingual artery as well as the inferior alveolar artery (the mylohyoid branch). The submental vessels supply the skin over the submental area. The submental artery also divides into the superficial and deep branch. The superficial branch anastomoses with the inferior labial artery. The deep branch also anastomoses with the inferior labial artery as well as the mental branch of the inferior alveolar artery.
Glandular Branches- These are 3-4 large branches that supply the submandibular salivary gland, as well as some structures that are found nearby i.e. the lymph nodes and integument.
Inferior Labial artery- This branch of the facial artery arises close to the corner (angle) of the mouth. It then passes superiorly and forwards in order to run beneath the triangularis (depressor anguli oris) muscle and pierces the orbicularis oris muscle. It supplies the mucous membrane and muscles of the lower lip and also supplies the labial glands. The vessel anastomoses with the artery of the opposite side and inferior alveolar artery (the mental branch).
Superior Labial artery- This a significantly larger and more tortuous branch of the facial artery when compared to the inferior labial artery. It supplies the upper lip and also gives a few branches that ascend to supply and nasal septum and ala of the nose.
Lateral nasal branch - This branch of the facial artery ascends along the lateral aspect of the nose. It supplies numerous structures, including the dorsum of the nose, the ala, and anastomoses with its contralateral fellow, the infraorbital branch of the internal maxillary artery as well as the dorsal nasal branch of the ophthalmic artery.
Angular artery (the terminal branch)- This is the final and terminal branch of the facial artery. On the cheek the artery supplies the lacrimal sac and orbicularis oculi and ultimately anastomoses with the ophthalmic artery (the dorsal nasal branch). It also ascends toward the medial angle of the orbit, and lies within the fibers of the quadratus labii superioris (a broad sheet of muscle that arises from the lateral aspect of the nose to the zygomatic bone). The terminal portion ultimately finishes at the medial canthus of the eye. It is accompanied by the greater occipital nerve, that innervates the scalp and provides sensation.
Palpation- Anaesthetists palpate the facial artery against the anteroinferior angle of the masseter muscle against the bony surface of the mandible.
Carotid Artery Vascular disease- Atherosclerosis (vascular disease) of the common carotid artery (commonly at its bifurcation) increases the risk of emboli shooting off and hence strokes occurring. Transient ischaemic attacks (a stroke where the symptoms resolve in less than 24 hours) are also more likely to occur. Treatment includes carotid endarterectomy, or endovascular treatment of the disease.