Maxillary nerve (CN V2)

  • The maxillary nerve (second division of fifth cranial nerve, second division of trigeminal nerve, maxillary division of trigeminal nerve, CN V2, latin: nervus maxillaris) is the second branch of the trigeminal nerve. The maxillary nerve contains general somatic afferent fibers that carry sensory information to the central nervous system (CNS) from the upper gingiva, the teeth of the upper jaw, the skin of the middle part of the face, the mucosa of the palate and the nasal cavity, the upper lip and the cheek.

    The maxillary nerve arising from the trigeminal ganglion in the middle cranial fossa leaves the cranial cavity through the foramen rotundum and emerges in the pterygopalatine fossa. Before leaving the cranial cavity the maxillary nerve gives a sensory branch to the meninges of the middle cranial fossa.

    Branches of the maxillary nerve can be categorized in groups by the location of their origins.

    • Originating in the cranial cavity: meningeal branch.
    • Originating in the pterygopalatine fossa: pterygopalatine nerves, zygomatic nerve, posterior superior alveolar nerve.
    • Originating in the infra-orbital canal: branches of the infraorbital nerve -  middle superior alveolar nerve, anterior superior alveolar nerve.
    • Originating on the face: branches of the infraorbital nerve - inferior palpebral branches, external nasal branches, superior labial branches.

    The meningeal branch of the maxillary nerve, also referred to as the middle meningeal nerve, arises in the cranial cavity just before the maxillary nerve enters the cavernous sinus, supplying the dura mater in the anterior part of the middle cranial fossa with sensory fibers.

    The pterygopalatine nerves (also known as sphenopalatine branches) are branches of the maxillary nerve within the pterygopalatine fossa, which descend to the pterygopalatine ganglion, but do not synapse there.

    The zygomatic nerve is a branch of the maxillary nerve, which arises in the pterygopalatine fossa and participates in innervating the skin of the face. The zygomatic nerve enters the orbit through the inferior orbital fissure, goes along the lateral wall of the orbit and divides into two branches, the zygomaticotemporal and zygomaticofacial nerves, which exit orbit through zygomaticotemporal foramen and zygomaticofacial foramen, respectively. The zygomatic nerve is mainly sensory as it carries sensory fibers to the CNS from the skin. However, it also has parasympathetic fibers - axons of the postganglionic neurons located in the pterygopalatine ganglion. The preganglionic fibers come via the facial nerve (CN VII) from neurons located in the superior salivatory nucleus in pons. The postganglionic parasympathetic fibers are carried within the zygomatic nerve and further in the zygomaticotemporal nerve, then they join the lacrimal nerve via a communicating branch, and thus reach and innervate the lacrimal gland.

    The zygomaticotemporal nerve is one of the branches of the zygomatic nerve, a sensory nerve arising from the maxillary nerve. The zygomaticotemporal nerve arises in a canal in the zygomatic bone and emerges on the face where it innervates the skin in the anterior area of the temporal region.

    The zygomaticofacial nerve is a branch of the zygomatic nerve, which emerges on the face and supplies the skin of the cheek region with sensory nerve fibers. The zygomaticofacial nerve passes along the inferolateral angle of the orbit, enters the zygomatic bone through zygomatico-orbital foramen, and emerges on the face through zygomaticofacial foramen. The nerve perforates the orbicularis oculi muscle and supplies the skin of the cheek with sensory fibers. It forms a nerve plexus together with the zygomatic branches of the facial nerve (CN VII) and the palpebral branches of the maxillary nerve (CN V2), specifically, with the inferior palpebral branches of the infraorbital nerve.

    The infraorbital nerve is a branch of the maxillary nerve, which provides sensory fibers to the skin of the lower eyelid, of the nose and the upper lip. The infraorbital nerve passes through the inferior orbital fissure into the infra-orbital groove and infra-orbital canal. The nerve emerges on the face through the infra-orbital foramen and then it branches into groups of nerves forming the so called pes anserinus minor on the face. The branches of the pes anserinus minor (inferior palpebral branches, external nasal branches, superior labial branches) innervate the skin of the lower eyelid, the nose (specifically, skin of ala nasi), and the skin of the upper lip. The infraorbital nerve also gives the anterior and middle superior alveolar nerves within the infra-orbital groove and canal.

    The set of superior alveolar nerves are branches of the maxillary nerve, which participate in forming the superior dental plexus that supplies teeth and gums with sensory nerve fibers.

    The posterior superior alveolar nerve is a branch of the maxillary nerve, which invests its sensory branches in the superior alveolar plexus. The posterior superior alveolar nerve arises from the maxillary nerve in the pterygopalatine fossa and goes anteroinferiorly, pierces the infratemporal surface of the maxilla and descends under the mucosa of the maxillary sinus. Then the nerve divides into smaller nerves, which link up and form a part of the superior alveolar plexus. The posterior superior alveolar nerve supplies sensory fibers to the molar teeth, as well as the upper gingiva and the adjoining part of the cheek.

    The middle superior alveolar nerve is a branch of the infraorbital nerve (a branch of the maxillary nerve), which provides sensory fibers to the superior dental plexus. The middle superior alveolar nerve arises from the infraorbital nerve in the infra-orbital groove (or from the infra-orbital canal), goes anteroinferiorly within the lateral wall of the maxillary sinus. It divides into smaller branches, which link up with the superior alveolar plexus supplying sensory fibers to the upper premolar teeth.This is a variable nerve, it can be absent, or there can be one or two of them.

    The anterior superior alveolar nerve is a branch of the infraorbital nerve (a branch of the maxillary nerve), which provides sensory fibers to the superior alveolar (dental) plexus. The anterior superior alveolar nerve arises from the infraorbital nerve near the middle of the infra-orbital canal. It crosses the anterior wall of the maxillary sinus, curves under the infraorbital foramen, then goes medially towards the nose and finally turns downwards, and divides into smaller branches which link with the superior alveolar plexus to supply the upper incisor and anterior lateral canine teeth with sensory fibers. The anterior superior alveolar nerve usually innervates all anterior teeth of the upper jaw, then loops backwards to join the middle superior alveolar nerve to form the superior alveolar plexus.

    The anterior superior nerve also gives off a nasal branch, which goes through a small canal in the lateral wall of the inferior nasal meatus innervating mucous membranes on the anterior aspect of the inferior meatus and the floor of the nasal cavity. The anterior superior nerve also communicates with the nasal branches arising from the pterygopalatine ganglion, and supplies the adjoining part of the nasal septum with its terminal nerve endings.

    The inferior palpebral branches are a set of sensory nerves arising from the infraorbital nerve (a branch of maxillary nerve), when it emerges on the face. These branches supply the skin of the lower eyelid with sensory fibers.

    The external nasal branches are a set of sensory nerves arising from the infraorbital nerve (branch of maxillary nerve) after it emerges from the infra-orbital canal to the face. They supply the skin of the ala (wings) of the nose with sensory fibers.

    The superior labial branches are a set of sensory nerves arising from the infraorbital nerve (branch of maxillary nerve) after it emerges on the face. These fibers provide sensory nerve fibers for the skin of the upper lip.