External carotid artery and its branches

Superior thyroid artery

The superior thyroid artery is the first branch of the external carotid artery. It arises from the external carotid artery at the level of the hyoid bone.

It descends from the anterior surface of the external carotid artery along the lateral border of the thyrohyoid muscle towards the apex of the thyroid gland.

The superior thyroid artery has several branches which include the superior laryngeal artery, arteries which supply the sternocleidomastoid, cricothyroid and infrahyoid muscles, as well as the anterior, posterior and lateral glandular branches.

The superior thyroid artery and its branches supply the sternocleidomastoid, cricothyroid and infrahyoid strap muscles, the thyroid gland and tissue of the upper part of the larynx.

You can remember the branches of the superior thyroid artery by using the mnemonic "I Shall Squeeze Charlie's Glutes", which stands for the branches of the superior thyroid artery; Infrahyoid, Superior laryngeal, Sternocleidomastoid, Cricothyroid and Glandular.

Ascending pharyngeal artery

The ascending pharyngeal artery arises from the medial surface of the external carotid artery between the internal carotid artery and pharynx to reach the base of the cranium. It is the smallest branch of the external carotid artery.

The ascending pharyngeal artery gives rise to the posterior meningeal artery, the inferior tympanic artery and several pharyngeal branches. Additionally, it gives off several unnamed branches which supply surrounding musculature. 

Structures supplied by the ascending pharyngeal artery include the pharynx, soft palate, the ear, meninges, muscles of the neck (longus capitis, longus coli), the sympathetic trunk, the hypoglossal, glossopharyngeal and vagus nerves as well as some cervical lymph nodes.

Lingual artery

The lingual artery arises from the anteromedial aspect of the external carotid artery at the level of the great cornu of the hyoid bone. It emerges from the external carotid artery between the superior thyroid and facial arteries and is divided into three parts according to the hyoglossus muscle. 

The first part of the lingual artery courses medially within the carotid triangle of the neck. It ascends and descends to form a loop which is crossed by the hypoglossal nerve. The second part of the lingual artery courses along the superior border of the hyoid bone and passes between the hyoglossus muscle and middle constrictor muscle of the pharynx. The third part of the lingual artery is also known as the deep lingual artery. At the anterior border of the hyoglossus muscle, the deep lingual artery ascends between the genioglossus muscle medially and the inferior longitudinal muscle of the tongue laterally.

Throughout its course the lingual artery gives off several branches which include the dorsal lingual, sublingual and deep lingual branches. The lingual artery also gives off branches which form a rich anastomosis that supplies the musculature of the tongue. The lingual artery provides arterial supply to the tongue and floor of the mouth.

Facial artery

The facial artery emerges from the external carotid artery just above the lingual artery within the carotid triangle. Occasionally the facial artery will arise from a common trunk with the lingual artery. It travels in an anterosuperior direction, deep to the digastric and stylohyoid muscles, curving around the inferior border of the mandible to enter the face. It ascends along the angle of the mouth and passes deep to the zygomaticus major and risorius muscles, ascending along the lateral side of the nose before terminating at the medial angle of the orbit.

The facial artery gives rise to the following branches including the ascending palatine, submental, inferior and superior labial and angular arteries as well as tonsillar and glandular branches. 

The facial artery ​supplies all structures in the face from the inferior border of the mandible anterior to the masseter muscle to the medial corner of the eye. It also supplies the soft palate, palatine tonsil, pharyngotympanic tube and submandibular gland.

Occipital artery

The occipital artery arises from the posterior aspect of the external carotid artery. It courses posterior and superiorly, deep to the posterior belly of the digastric muscle. It passes between the transverse process of the atlas (C1) and the mastoid process of the temporal bone. It extends through the occipital groove of the temporal bone where it is joined by the greater occipital nerve. It pierces the investing layer of deep cervical fascia to ascend within the dense superficial fascia of the scalp.

Main branches of the occipital artery include the upper and lower sternoclediomastoid branches. Additionally the occipital artery gives off the auricular, mastoid, occipital, meningeal and descending branches.

The occipital artery supplies the sternocleidomastoid, trapezius and deep muscles of the neck as well as the meninges, pinna of the ear and mastoid air cells.

Posterior auricular artery

The posterior auricular artery arises from the posterior aspect of the external carotid artery, above the posterior belly of digastric. It ascends in the neck between the parotid gland and styloid process. It then travels in a groove which lies between the auricular cartilage and mastoid process of the temporal bone.

The posterior auricular artery gives off the stylomastoid and posterior tympanic arteries as well as auricular, occipital and parotid branches.

Within the neck the posterior auricular artery provides arterial supply to the digastric, stylohyoid and sternocleidomastoid muscles as well as the parotid gland. Within the head the posterior auricular artery supplies the extrinsic auricular muscles, the external acoustic meatus, the auricle, middle ear, facial nerve and mastoid air cells.

Maxillary artery

The maxillary artery is the larger of the two terminal branches and arises from the external carotid artery within the parotid gland. From the parotid gland, the maxillary artery passes anteriorly between the neck of the mandible and the sphenomandibular ligament to enter the infratemporal fossa. It then extends between the pterygoid muscles to enter the pterygopalatine fossa via the pterygomaxillary fissure.

The maxillary artery is divided into three parts according to its location. The first part is located between the neck of the mandible and sphenomandibular ligament. The second part is associated with the lateral pterygoid muscle while, the third part lies within the pterygopalatine fossa. 

Branches of the first part include: the middle meningeal and inferior alveolar arteries as well as the smaller deep auricular, anterior tympanic and accessory meningeal arteries. 

Branches of the second part include: the deep temporal, masseteric, buccal and pterygoid arteries. 

Finally, branches of the third part include the posterior superior alveolar, infraorbital, pharyngeal, descending palatine and sphenopalatine arteries as well as the artery of the pterygoid canal.

The maxillary artery supplies many structures some of which include the upper and lower jaw, teeth, muscles of mastication, ears, nose, meninges and palate.

Why not test yourself on the muscles innervated by the branches of the maxillary artery with flashcards?  

Superficial temporal artery

The superficial temporal artery arises as the smaller terminal branch of the external carotid artery. It similarly arises within the substance of the parotid gland behind the neck of the mandible. It ascends from the parotid gland superficially alongside the auriculotemporal nerve to the scalp. It terminates by dividing into its terminal frontal and parietal branches.

Branches of the superficial temporal artery include the transverse facial, zygoaticoorbital and middle temporal arteries. Additionally it provides parotid, anterior auricular, occipital frontal and parietal branches.

The superficial temporal artery provides arterial supply to the skin and muscles of the side of the face and scalp. It also provides arterial supply to the parotid gland and temporomandibular joint.