Pterygopalatine Fossa and Palate - LO 7

Maxillary nerve [10:07]

7. What are the major branches of the maxillary n. (V2)? Are these branches motor, sensory, or both? What structures do these nerves innervate?

The maxillary nerve is the 2nd division of the trigeminal n. and is wholly afferent (sensory). It enters the pterygopalatine fossa via the foramen rotundum and is closely associated with the pterygopalatine ganglion.

V2 nerve, main trunk branches:

- Zygomatic n.
  - Exits pterygopalatine fossa via the inferior orbital fissure
  - Terminal branches:
    - zygomaticofacial n.
    - zygomaticotemporal n.
- Posterior superior alveolar n.
  - Innervates maxillary sinus & joins superior alveolar (dental) plexus to innervate maxillary molars

- Infra-orbital n.
  - Terminal branch of V2
  - Complex route: begins in pterygopalatine fossa, enters the orbit through the inferior orbital fissure, travels through the infra-orbital canal, and exits the infra-orbital foramen to afferently serve the midface
  - Two main branches:
    - Middle superior alveolar n. (MSAN): variable
      - Supplies maxillary premolars (part of superior dental plexus) and maxillary sinus
    - Anterior superior alveolar n. (ASAN)
      - Afferent innervation to maxillary incisors and canines (part of superior dental plexus)
      - Small portions of maxillary sinus and nasal cavity floor
  - Exits skull via infra-orbital foramen and has small nasal, palpebral, and superior labial brs.

V2 nerve branches associated with the pterygopalatine ganglion (do NOT synapse in ganglion):

- Nasopalatine n.
  - Pterygopalatine fossa → Sphenopalatine foramen → Nasal cavity → Nasal septum (vomer) → Incisive fossa → Hard palate (communicates with greater palatine n.)
  - Afferent innervation to: inferior nasal septum and anterior hard palate
- Posterior superior nasal nn. (PSN) (lateral & medial)
  - Like nasopalatine, enter the nasal cavity via the sphenopalatine foramen
  - Posterior superior lateral nasal nn.
    - Afferent innervation: posterior ethmoidal sinus and superior and middle nasal conchae
  - Posterior superior medial nasal nn.
    - Afferent innervation: posterior portion of roof of nasal septum

- Palatine nn.
  - Both greater & lesser palatine nn. descend from the pterygopalatine ganglion through the greater palatine canal to the hard & soft palates
  - Greater palatine n.
    - Enters the hard palate area via the greater palatine foramen
  - Lesser palatine n.
    - Provides sensory innervation for the soft palate, and enters this area via the lesser palatine foramen

- Pharyngeal n.
  - Unique in that it exits from the pterygopalatine ganglion posteriorly
  - Afferent innervation: mucosa posterior to the pharyngotympanic tube

D1 S7 Chart Maxilla (V2)