Trigeminal Nerve Anatomy and Functions

Trigeminal Nerve

The trigeminal nerve controls masticatory muscles. Its sensory fibers receive sensitivity from the face, orbit, nasal cavity, and oral cavity. The trigeminal ganglion (semilunar ganglion/gasserian ganglion) is located anterosuperior to the petrous portion of the temporal bone.

V1 (Ophthalmic Nerve)

V1 is sensory and supplies the front region of the nose, upper eyelid, mucous membranes of the frontal, sphenoid, and ethmoid sinuses, the upper part of the nasal cavity, and the eyeball. V1 has three terminal branches: nasal, frontal, and lacrimal.

Nasal Nerve

• Collateral branches: long ciliary nerve (supplies the eyeball), posterior ethmoidal nerve (supplies the sphenoid sinus, ethmoid cells, and upper portion of the nasal cavity).
• Terminal branches: anterior ethmoidal nerve (branches into internal nasal and external nasal nerves, supplying the nasal pyramid), and infratrochlear nerve (supplies the skin of the glabella and tear duct).

Frontal Nerve

The frontal nerve receives sensitivity from the frontal and epicranial regions.

• Terminal branches: supraorbital nerve (supplies the skin of the forehead, epicranium, and medial portion of the upper eyelid) and supratrochlear nerve (anastomoses with the infratrochlear nerve and supplies the skin of the glabella and root of the nose).

Lacrimal Nerve

The lacrimal nerve innervates the lacrimal gland with fibers from CN7 and receives sensitivity from the lateral portion of the upper eyelid. It communicates with the supratrochlear nerve and zygomatic nerve.

V2 (Maxillary Nerve)

V2 supplies the skin of the cheek, lower eyelid, nose, upper lip, mucosa of the lower part of the nasal cavity, maxilla, and tooth roots.

• Collateral branches: zygomatic, pterygopalatine, posterior superior alveolar, middle superior alveolar, and anterior superior alveolar.
• Terminal branch: infraorbital.

Zygomatic Nerve

The zygomatic nerve communicates with the lacrimal nerve and receives parasympathetic fibers from the pterygopalatine ganglion and sympathetic fibers from the facial nerve to control the lacrimal gland.

• Terminal branches: zygomaticotemporal nerve (supplies the skin of the temporal region and communicates with CN7 and the lacrimal nerve) and zygomaticofacial nerve (crosses the zygomaticofacial foramen and supplies the skin of the cheek).

Pterygopalatine Nerve

• Terminal branches: orbital branches, posterior superior alveolar, nasal, pharyngeal, greater palatine, lesser palatine, and nasopalatine.

• Nasopalatine nerve: supplies the anterior palate.
• Greater palatine nerve: branches in the mucosa of the soft and hard palate.
• Lesser palatine nerve: branches in the mucosa of the soft palate.

Posterior Superior Alveolar Nerve

Supplies the molars and premolars region. With other superior alveolar nerves, it forms the superior dental plexus.

Middle Superior Alveolar Nerve

A branch of the infraorbital nerve that supplies the maxillary sinus and premolars.

Anterior Superior Alveolar Nerve

A branch of the infraorbital nerve that supplies the incisors.

Infraorbital Nerve

• Collateral branches: middle superior alveolar and anterior superior alveolar.
• Terminal branches: palpebral (lower eyelid), nasal branch (skin of the nose), and labial (upper lip and cheek).