Pterygopalatine Fossa

Pterygopalatine FossaI

I. Boundaries and Openings

• A. Anterior wall : posterior surface of the maxilla or the posterior wall of the maxillary sinus (no openings).
• B. Posterior wall : pterygoid process and greater wing of the sphenoid. Openings and their contents include the following:
• Foramen rotundum to middle cranial cavity : maxillary nerve.
• Pterygoid canal to foramen lacerum : nerve of the pterygoid canal.
• Palatovaginal (pharyngeal or pterygopalatine) canal to choana : pharyngeal branch of the maxillary artery and pharyngeal nerve from the pterygopalatine ganglion.
• C. Medial wall : perpendicular plate of the palatine. The opening is the sphenopalatine foramen to the nasal cavity , which transmits the sphenopalatine artery and nasopalatine nerve.
• D. Lateral wall : open (the pterygomaxillary fissure to the infratemporal fossa).
• E. Roof : greater wing and body of the sphenoid. The opening is the inferior orbital fissure to the orbit, which transmits the maxillary nerve.
  F. Floor : fusion of the maxilla and the pterygoid process of the sphenoid. The opening is the greater palatine foramen to the palate, which transmits the greater palatine nerve and vessels.
  

II. Contents

A. Maxillary nerve

• Passes through the lateral wall of the cavernous sinus and enters the pterygopalatine fossa through the foramen rotundum.
• Is sensory to the skin of the face below the eye but above the upper lip.
• Gives rise to the following branches:

1. Meningeal branch

• Innervates the dura mater of the middle cranial fossa.

2. Pterygopalatine nerves (communicating branches)

• Are connected to the pterygopalatine ganglion.
• Contain sensory fibers from the trigeminal ganglion.

3. Posterior-superior alveolar nerves

• Descend through the pterygopalatine fissure and enter the posterior-superior alveolar canals.
• Innervate the cheeks, gums, molar teeth, and maxillary sinus.

4. Zygomatic nerve

• Enters the orbit through the inferior orbital fissure and divides into the zygomaticotemporal and zygomaticofacial branches, which supply the skin over the temporal region and over the zygomatic bone, respectively.
• Transmits postganglionic parasympathetic and sympathetic GVE fibers to the lacrimal gland through the zygomaticotemporal branch, which joins the terminal part of the lacrimal nerve.

5. Infraorbital nerve

• Enters the orbit through the inferior orbital fissure and runs through the infraorbital groove and canal.
• Emerges through the infraorbital foramen and divides in the face into the inferior palpebral, nasal, and superior labial branches.
• Gives rise to the middle and anterior-superior alveolar nerves, which supply the maxillary sinus, teeth, and gums.

6. Branches (sensory) via the pterygopalatine ganglion

• Contain GSA fibers as branches of the maxillary nerve but also carry GVA and GVE fibers from the facial nerve to the nasal mucosa and the palate.
• Orbital branches
  
  • Supply the periosteum of the orbit and the mucous membrane of the posterior ethmoidal and sphenoidal sinuses.

• Pharyngeal branch
• Runs in the pharyngeal (palatovaginal) canal and supplies the roof of the pharynx and the sphenoidal sinuses.
• Posterior-superior lateral nasal branches
• Enter the nasal cavity through the sphenopalatine foramen and innervate the posterior part of the septum, the posterior ethmoidal air cells, and the superior and middle conchae.
• Greater palatine nerve
• Descends through the palatine canal and emerges through the greater palatine foramen to innervate the hard palate and the inner surface of the maxillary gingiva.
• Gives rise to the posterior-inferior lateral nasal branches.
• Lesser palatine nerve
  
  • Descends through the palatine canal and emerges through the lesser palatine foramen to innervate the soft palate and the palatine tonsil.
  • Contains sensory (GVA and taste) fibers (for the soft palate) that belong to the facial nerve and have their cell bodies in the geniculate ganglion.
  • Also contains postganglionic parasympathetic and sympathetic GVE fibers that come from the facial nerve via the greater petrosal and vidian nerves and supply mucous glands in the nasal cavity and the palate.

• Nasopalatine nerve
• Runs obliquely downward and forward on the septum, supplying the septum, and passes through the incisive canal to supply the hard palate and the gum.

B. Pterygopalatine ganglion

• Is formed by neuron cell bodies of parasympathetic postganglionic GVE fibers and lies in the pterygopalatine fossa just below the maxillary nerve, lateral to the sphenopalatine foramen and anterior to the pterygoid canal.
• Receives preganglionic parasympathetic fibers from the facial nerve by way of the greater petrosal nerve and the nerve of the pterygoid canal.
• Sends postganglionic parasympathetic fibers to the nasal and palatine glands and to the lacrimal gland by way of the maxillary, zygomatic, and lacrimal nerves.
• Also receives postganglionic sympathetic fibers (by way of the deep petrosal nerve and the nerve of the pterygoid canal), which are distributed with the postganglionic parasympathetic fibers.

C. Pterygopalatine part of the maxillary artery

• Supplies blood to the maxilla and maxillary teeth, nasal cavities, and palate.
• Gives rise to the posterior-superior alveolar artery, infraorbital artery (which gives rise to anterior- superior alveolar branches), descending palatine artery (which gives rise to the lesser palatine and greater palatine branches), artery of the pterygoid canal, pharyngeal artery, and sphenopalatine artery.

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