Nasopalatine nerve

Origin and path?

The nasopalatine nerve originates from the pterygopalatine ganglion (gangl. pterigopalatinum), the branches of which receive sensory fibers from the maxillary nerve (n. maxillaris — V2 branch of the trigeminal nerve).

Topography and course of the nerve:

• Entry into the nasal cavity: The nerve enters the nasal cavity from the pterygopalatine fossa through the sphenopalatine foramen (foramen sphenopalatinum).
• Course along the septum: It lies between the periosteum and the mucosa of the nasal septum, running downward and forward.
• Exit onto the palate: It reaches the incisive canal (canalis incisivus), passes through it, and emerges onto the hard palate via the incisive foramen (foramen incisivum).

What does the nasopalatine nerve innervate?

As a sensory nerve, it innervates the following structures:

• Nasal septum: Mucosa of the upper part of the nasal septum.
• Hard palate: A triangular area of mucosa in the anterior hard palate between the canines.
• Palatine tonsil (tonsilla palatina): Participates in its innervation together with the palatine nerves and pharyngeal plexus.

Anastomoses: The nasopalatine nerve anastomoses with its counterpart from the opposite side. In addition, within or just prior to entering the incisive canal, it gives off anastomotic branches to the anterior division of the superior dental plexus (plexus dentalis).

Topography and adjacent structures

On the hard palate from the oral cavity, the nasopalatine nerve is located in the region of the incisive papilla (papilla incisiva), which lies anterior to the palatine raphe.

In this anatomical region, it is adjacent to:

• Arteries: Posterior septal branch of the sphenopalatine artery (a. nasalis posterior septi).
• Other palatine nerves: Greater palatine nerve (n. palatinus major) and lesser palatine nerves (nn. palatini minores).
• Tissues: Palatine glands (gll. palatinae).

Clinical significance: Incisive anesthesia

To anesthetize the area innervated by the nasopalatine nerve, incisive anesthesia is used in dentistry. The anatomical landmark is the incisive foramen, located 7–8 mm posterior to the gingival margin between the central incisors, just behind the incisive papilla.

Technique:

• Intraoral approach: The patient's head is tilted back. Following topical anesthesia, the needle is inserted into the mucosa of the incisive papilla slightly anterior to the foramen orifice, because inserting the needle directly over the foramen would misalign it with the axis of the incisive canal due to obstruction by the mandible. The anesthetic is injected by diffusion until bone contact is made or via the intracanal route, advancing the needle 0.5–0.75 cm into the canal to block the anastomotic branch to the anterior superior dental plexus.
• Intranasal approach (extraoral access): Injection and drug administration are performed at the base of the nasal septum on both sides. Used when the intraoral approach is impossible or when a combination of bilateral infraorbital anesthesia and intraoral nasopalatine nerve block does not completely relieve pain in the central incisors.

Class and exam questions

What else to study on this topic

• Pterygopalatine ganglion (ganglion pterygopalatinum)
• Maxillary nerve (n. maxillaris)
• Incisive canal and incisive foramen
• Incisive anesthesia

Other topics in the "Anatomical Structures" section

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