Branches of the internal maxillary artery and of the carotid plexus:
1. A. alveolaris inferior ([Fig. 120], j).—The inferior alveolar (or inferior dental) artery leaves the inferior maxillary just opposite the condyloid process of the mandible. It enters the mandibular canal by the mandibular foramen, along with the nerve of the same name, and traverses the canal, furnishing branches to the lower teeth. It emerges at the mental foramen, and its terminal branches are distributed to the chin, but a branch is continued in the bone beyond the mental foramen and supplies the incisor and canine teeth of the lower jaw.
2. A. meningea media ([Fig. 120], k).—The middle meningeal is a large vessel which leaves the internal maxillary at about the same level as the inferior alveolar. It passes into the foramen ovale and ramifies in the dura mater. Its branches leave distinct impressions on the inner surface of the bones of the skull.
3. A large branch ([Fig. 121], h) from the plexus passes into the cranial cavity through the orbital fissure and lies within the skull at the side of the hypophysis. It gives off the following branches:
a. A posterior communicating branch, very short, which extends caudad and joins the internal carotid artery ([Fig. 121], g).
b. A. cerebri media ([Fig. 121], i).—The middle cerebral artery passes dorsad on the side of the cerebral hemisphere along the fissure of Sylvius and divides into numerous branches which are distributed to the surface of the cerebrum.
c. A. cerebri anterior ([Fig. 121], j) Passes dorsad between the cerebral hemispheres. Just craniad of the optic chiasma the two anterior cerebral arteries are united by a small communicating branch, thus completing the circulus arteriosus or circle of Willis ([Fig. 121]), surrounding the hypophysis (see [page 292]).
4. From the carotid plexus several branches pass, arising either separately or in common, to the masseter, temporal, and pterygoid muscles.
5. A. ophthalmica ([Fig. 120], n).—The ophthalmic artery passes from the carotid plexus to the structures in the orbit. It gives off numerous branches which supply the muscles of the eyeball, and other structures of this region. It sends an ethmoidal branch into the nasal cavity through the ethmoidal foramen in the orbital plate of the frontal bone, then continues distad to emerge from the orbit on the medial side of the eye; here it anastomoses with branches of the superficial temporal.
6. A. palatina minor ([Fig. 120], p).—The lesser palatine artery leaves the internal maxillary distad of the carotid plexus, near the caudal border of the maxillary bone. It passes ventrocaudad into the soft palate.