Trigeminal Nerve Overview Quiz

Trigeminal Nerve Overview

• The trigeminal nerve has two roots: a larger sensory root and a smaller motor root, emerging from the pons.
• Sensory root contains central processes from sensory nerve cell bodies located in the trigeminal (semilunar/Gasserian) ganglion.
• Trigeminal ganglion is situated under the dura mater in Meckel’s cave, near the petrous portion of the temporal bone.

Divisions of the Trigeminal Nerve

• The ophthalmic division exits the skull via the superior orbital fissure.
• The maxillary division exits through the foramen rotundum.
• The motor root of the mandibular division runs medial to the sensory root before passing through the foramen ovale.

Maxillary Division (V2)

• Exclusively contains sensory fibers supplying maxillary teeth, palate, maxillary air sinus, much of the nasal cavity, and specific facial skin regions.
• Enters the pterygopalatine fossa through foramen rotundum and bifurcates into four branches.

Innervation of the Palate

• The palatine nerves derive from the maxillary division (V2).
• Nasopalatine nerve supplies a small area behind the maxillary incisors.
• Greater palatine nerve supplies most of the hard palate, along with fibers from the pterygoid canal.
• Lesser palatine foramen innervates part of the soft palate; glossopharyngeal nerve supplies the remainder.

Posterior Superior Alveolar Nerve (PSA)

• The PSA branches off just before entering the infraorbital foramen and supplies maxillary molars, periodontal ligaments, alveolar bone, and adjacent facial gingiva.
• Exception: does not innervate the mesiobuccal root of the first molar (supplied by MSAN).

Infraorbital Nerve

• Becomes the infraorbital nerve after entering the infraorbital fissure and canal.
• Gives off middle superior alveolar (MSA) and anterior superior alveolar (ASA) branches.
• MSA supplies the floor of the maxillary sinus and enters premolars through small foramina.

Innervation of Maxillary Teeth

• MSA supplies pulp and supporting alveolar bone of maxillary premolars and molars.
• ASA provides dental branches to maxillary incisors.
• Distribution of MSA, ASA shows variability; MSA may occasionally be absent.

Mandibular Division (V3) Overview

• Contains both motor and sensory fibers; only division of the trigeminal nerve with motor fibers.
• Exits the skull via foramen ovale into the infratemporal space.
• Divides into four main branches: buccal, lingual, inferior alveolar, and auriculotemporal.

Branches of the Mandibular Division

• Each main branch further divides into smaller branches, including:
  • Buccal nerve: supplies sensation to the buccal mucosa.
  • Lingual nerve: supplies sensation to the tongue.
  • Inferior alveolar nerve: enters mandibular canal to provide innervation to the lower teeth.
  • Auriculotemporal nerve: supplies regions of the ear and temporomandibular joint.

Test your knowledge on the anatomy and functions of the trigeminal nerve, including its divisions and innervation specifics. This quiz covers key concepts about the sensory and motor roots, as well as the maxillary division's role in facial sensation.