External carotid artery
The arteria carotis externa also moves towards the skull and its branches supply parts of the head, the facial region and the meninges, among others. It usually runs in front of the internal carotid artery and crosses the hypoglossal and glossopharyngeal nerves. In total, the external carotid artery gives off 8 branches in its course.
The first branch to emerge from the external carotid artery is the superior thyroid artery at the level of the hyoid bone (Os hyoideum), a bone at the base of the mouth below the tongue. It moves to the thyroid gland, whose upper part supplies it with blood. Furthermore, parts of the larynx are supplied by its branch, the Arteria laryngea superior.
Other branches go to muscles above and below the hyoid bone (infrahyoid and suprahyoidal muscles) and to the sternocleidomastoid muscle of the neck. Above the arteria thyroidea superior, the arteria pharyngea ascendens usually emerges from the arteria carotis externa as the second branch. It moves in the lateral wall of the pharynx, which also supplies it, in the direction of the skull base.
Its branches supply the tympanic cavity of the ear (Arteria tympanica inferior) and the meninges at the back of the cranial fossa (Arteria meningea posterior). Another branch of the external carotid artery is the lingual artery. It runs across the oral cavity to the tongue, where it winds its way to the tip of the tongue.
Besides the tongue, it also supplies the floor of the mouth with blood. At the level of the angle of the jaw, the facial artery originates from the external carotid artery. It runs from the lower jaw towards the face, past the corner of the mouth and the nose to the central corner of the eye.
It supplies the upper and lower lip of the mouth. At the neck, the facial artery gives off the arteria palatina ascendens, which supplies the side wall of the pharynx with blood. Other branches of the facial artery are the submental artery, which supplies the muscles above the hyoid bone and the submandibular gland (Glandula submandibularis), and the ramus tonsillaris, which leads to the palatal tonsil.
A further branch of the Arteria carotis externa is the Arteria occipitalis, which runs to the back of the head and supplies parts of the lateral and rear surface of the head as well as parts of the meninges with blood. The last branch before the arteria carotis externa splits into its end branches is the arteria auricularis posterior. It extends under the parotid gland in the direction of the ear and supplies the pinna, middle and inner ear as well as the tympanic cavity of the ear.
At the level of the jaw angle, the external carotid artery divides into its end branches, the maxillary artery and the superficial temporal artery. The stronger of the two is the arteria maxillaris, which gives off a total of 13 branches and supplies the facial region. The weaker end branch is the Arteria temporalis superficialis.
It runs between the head of the lower jaw and the external auditory canal into the temporal region. It supplies the parotid gland, parts of the pinna and the external auditory canal. It also gives a branch to the mimic muscles of the face, the arteria transversa faciei.