Maxillary Nerve
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Direct answer
The cheek, upper lip, upper teeth and gums, the mucosa of the hard palate and most of the nasal cavity draw their sensation from the maxillary nerve, V2, the purely sensory second division of the trigeminal. It leaves the trigeminal ganglion, exits the middle cranial fossa through the foramen rotundum, crosses the pterygopalatine fossa where it links with the pterygopalatine ganglion, and enters the orbit through the inferior orbital fissure to continue as the infraorbital nerve onto the face. Its distribution is the zone shattered in Le Fort fractures, and its infraorbital nerve is the one a surgeon warns a patient about before maxillary and orbital floor surgery.
What you must remember
- In the lateral wall of the cavernous sinus it lies below V1; through the foramen rotundum it reaches the pterygopalatine fossa.
- Secretomotor and sympathetic fibres to the nose, palate and lacrimal gland hitch-hike along its ganglionic branches, relay in the pterygopalatine ganglion, and travel with V2 branches without V1 being involved distal to the orbit.
- The zygomatic nerve enters the orbit through the inferior orbital fissure and divides into zygomaticofacial and zygomaticotemporal branches; the zygomatic nerve also carries the parasympathetic supply onward to the lacrimal gland.
- Three superior alveolar nerves — posterior (on the tuberosity of the maxilla), middle and anterior (from the infraorbital nerve in its canal) — supply the upper teeth and maxillary sinus.
- The infraorbital nerve emerges through the infraorbital foramen roughly 8 mm below the orbital margin on the canine fossa, dividing into palpebral, nasal and labial branches.
- The greater and lesser palatine and nasopalatine branches reach the palate and nasal septum via the ganglion; the pharyngeal branch supplies the nasopharynx roof.
- Sensory loss over cheek and upper lip with a fractured middle third of the face points to this nerve.
A typical exam case that uses this nerve end to end
A young man struck on the face in a road traffic accident arrives with mobility of the maxilla, anaesthesia of the right cheek and upper lip, and numbness of the upper gum and teeth — a textbook Le Fort injury traced along V2. Work along the nerve's course to localise. The fracture line of a Le Fort I runs through the piriform aperture, lateral nasal wall and maxillary walls near the alveolar process, disturbing the posterior superior alveolar nerves; a Le Fort II pyramidal fracture crosses the infraorbital rim at the infraorbital foramen, where the emerging infraorbital nerve is crushed against its bony margin; a Le Fort III passes the zygomaticofrontal suture and orbital walls, catching the nerve within the inferior orbital fissure. In each, the level of numbness maps the fracture.
Investigation and management follow the same anatomy. A CT of the facial skeleton defines the fracture; the sensory deficit over the cheek is documented before any plate fixation of the infraorbital rim, because the nerve is decompressed by accurate reduction of the foramen region. Per current maxillofacial practice, open reduction and internal fixation of displaced fractures addresses both deformity and nerve recovery, with infraorbital nerve function monitored over months. For the dentist, the same nerve's superior alveolar branches are the target of the posterior superior alveolar block for upper molar anaesthesia.
Where students slip
The recurring error is to route the parasympathetic supply of the lacrimal gland through "V1 all the way"; the fibres leave the brainstem with the greater petrosal nerve, relay in the pterygopalatine ganglion, join the zygomatic branch of V2 and only then cross to the lacrimal nerve — so V2 is a genuine carrier of secretomotor fibres even though it is sensory by right. Second, candidates forget that the maxillary nerve "passes across" the pterygopalatine ganglion rather than through it; the ganglion hangs below the nerve in the fossa, connected by short ganglionic branches, a distinction that decides many one-mark questions. Third, the infraorbital foramen is placed "below the orbital margin" — the expected measurement is about 8 mm, in line with the pupil when the eye looks straight ahead, and this surface landmark is what the examiner wants before an infraorbital block.
Frequently asked questions
Which foramen transmits the maxillary nerve?
The foramen rotundum, leading from the middle cranial fossa into the pterygopalatine fossa.
Which branches supply the upper teeth?
The posterior, middle and anterior superior alveolar nerves, the last two given off by the infraorbital nerve within the infraorbital canal.
What is the surface marking of the infraorbital foramen?
About 8 mm below the inferior orbital margin on the canine fossa, in a vertical line through the pupil of the eye in the neutral gaze.
Which fracture classically causes cheek and upper lip anaesthesia?
Le Fort II, as the pyramidal fracture crosses the infraorbital rim and injures the infraorbital nerve at its foramen.
Does the maxillary nerve carry parasympathetic fibres?
Yes, as a passenger — secretomotor fibres from the pterygopalatine ganglion for the nose, palate and, via the zygomatic and lacrimal nerves, the lacrimal gland.