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The pterygopalatine fossa is the region between the pterygomaxillary fissure and the nasal cavity. The fossa accommodates branches of the maxillary nerve [cranial nerve (CN) V-2], the pterygopalatine ganglion, and the terminal branches of the maxillary artery.
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Boundaries of the Pterygopalatine Fossa
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The pterygopalatine fossa is an irregular space where neurovascular structures course through to the nasal cavity, palate, pharynx, orbit and face (Figure 22-1A and B). The neurovascular structures enter and exit the fossa through the following boundaries:
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- Anterior boundary. Posterior surface of the maxilla.
- Posterior boundary. Pterygoid processes and the greater wing of the sphenoid bone, with openings for the following structures:
- Foramen rotundum for CN V-2.
- Pterygoid canal for the nerve of the pterygoid canal (Vidian nerve).
- Pharyngeal (palatovaginal) canal for the pharyngeal branch of CN V-2.
- Medial boundary. Perpendicular plate of the palatine bone containing the sphenopalatine foramen, which transmits the nasopalatine nerve (CN V-2 branch) and the sphenopalatine artery.
- Lateral boundary. Pterygomaxillary fissure, which communicates with the infratemporal fossa.
- Superior boundary. Greater wing and body of the sphenoid bone, with the infraorbital fissure transmitting the infraorbital nerve and the vessels in the orbit.
- Inferior boundary. Palatine process of the maxilla and the pterygoid process of the sphenoid bone with the greater and lesser palatine canals and foramina, which transmit the greater and lesser palatine nerves and vessels.
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Innervation of the Pterygopalatine Fossa
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Branches of CN V-2 form most of the nerves that enter and exit the pterygopalatine fossa (Figure 22-1C and D). CN V-2 enters the fossa via the foramen rotundum and branches as follows:
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- Posterior superior alveolar nerves. Enters the posterior superior alveolar canals, providing general sensation to the maxillary molar teeth and gingivae.
- Infraorbital nerve. Courses through the infraorbital fissure, groove, canal, and ultimately the foramen providing general sensation to the inferior eyelid, the lateral nose, and the superior lip. The infraorbital nerve also gives rise to the middle and anterior superior alveolar nerves, which supply the maxillary premolars, canines, and incisors, and the gingivae and mucosal lining of the maxillary sinus.
- Zygomatic nerve. Enters the orbit via the infraorbital fissure, dividing into the zygomaticotemporal and zygomaticofacial nerves, which supply the skin over the zygomatic arch and the temporal region. In addition, the zygomatic nerve communicates with the lacrimal nerve in the orbit and carries parasympathetic neurons from the pterygopalatine ganglion to the lacrimal gland.
- Pharyngeal nerve. Courses through the pharyngeal canal, supplying part of the nasopharynx.
- Greater and lesser palatine nerves....