Anatomy

The Trigeminal Nerve is the fifth of the Twelve Cranial Nerves, which is divided into three main branches: the ophthalmic nerve, the maxillary nerve and The Mandibular Nerve. Its second division is the maxillary branch, which consists of afferent sensory fibers, parasympathetic and sympathetic fibers. The word afferent means toward the centre, as in from a peripheral area of a limb to the central nervous system. The word efferent is the opposite of afferent, meaning away from the centre and toward the periphery; when the stimulus is carried back to the Brain from a peripheral area.

Pathway

The pathway for afferent sensory fibers of the maxillary nerve from the proprioceptors until the trigeminal nuclei (after the merger into one main cranial nerve) is the following (from the initiation in the periphery to the termination in the brain):

  • The second facial area that is innervated by a division of the trigeminal nerve (see image), consists of the area under the tip of the nose, the nostrils, the upper lip, the zygomatico-facial area and a section of the temporal area.
  • The maxillary nerve branches that innervate the maxillary area or the second facial area include the major and minor palatine nerves, the recurrent pharyngeal nerve, the posterior superior nasal nerves, the nasopalatine nerve and the superior alveolar nerve which all synapse on the pterygo-palatine ganglion.
  • Other maxillary nerve branches that don’t synapse upon the pterygo-palatine ganglion but directly continue into the main branch of the maxillary nerve include the infraorbital nerve and the zygomatic nerve branches, namely the recurrent zygomaticofacial nerve and the zygomaticotemporal nerve.
  • The main branch of the zygomatic nerve is an exception because it doesn’t directly synapse on the pterygo-palatine ganglion, but it does carry both sympathetic and parasympathetic fibers from the ganglion to the lacrimal gland.
  • The recurrent meningeal nerve is a small branch stemming from the maxillary nerve itself.
  • The maxillary nerve synapses on the gasseri ganglion (ganglion of the trigeminal nerve).
  • The postganglionic fibers continue to the pontine nucleus and the spinal nucleus and tract.

Reference: Frank H. Netter, Atlas der Anatomie, 5th Edition (Bilingual Edition: English and German), Saunders, Chapter 1, Plate 121, published 2010.

Author: Dr. Alexandra Sierosławska

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