Pterygopalatine Fossa Anatomy
The pterygopalatine fossa lies between the pterygoid process of the sphenoid bone posteriorly, the palatine bone medially and the maxilla anteriorly (Fig. 7.43). It is slit-like and opens laterally through the pterygomaxillary fissure into the infratemporal fossa.
It contains part of the maxillary (V2) division of the trigeminal nerve, the pterygopalatine ganglion and its branches and the termination of the maxillary artery, together with accompanying veins and lymphatics. The pterygopalatine fossa communicates with the middle cranial fossa through the foramen rotundum, with the foramen lacerum through the pterygoid canal, with the orbit through the inferior orbital fissure, with the walls of the nasal cavity through the sphenopalatine foramen and with the palate via the greater and lesser palatine canals.
Maxillary (V2) division of the trigeminal nerve
The maxillary division (Fig. 7.44) leaves the cranial cavity through the foramen rotun- dum, crosses the pterygopalatine fossa and continues forwards through the inferior orbital fissure into the orbit. It terminates as the infraorbital nerve, which traverses the infraorbital canal to reach the face. The maxillary division has several branches arising in the pterygopalatine fossa and the floor of the orbit. In the pterygopalatine fossa (Fig. 7.45), two branches suspend the pterygopalatine ganglion from the parent nerve. Also arising in the fossa are the posterior superior alveolar nerves (Figs 7.44 & 7.45), which descend in the posterior wall of the maxillary air sinus to reach the upper molar teeth. In the floor of the orbit, the middle and anterior superior alveolar nerves (Fig. 7.44) arise and descend in the lateral and anterior walls of the maxilla. Collectively, the superior alveolar nerves supply the maxilla and its air sinus, the alveolar ridge and all the upper teeth. The zygomatic nerve (Fig. 7.44) also arises in the floor of the orbit and ascends on the lateral wall, dividing into zygomaticotemporal and zygomaticofacial nerves. These branches pierce the zygomatic bone to supply the overlying facial skin. A branch from the zygomaticotemporal nerve conveys postganglionic parasympathetic fibres from the pterygopalatine ganglion to the lacrimal gland. The infraorbital nerve (Fig. 7.44) emerges onto the face through the infraorbital foramen and supplies the skin of the cheek, lower eyelid, upper lip and lateral surface of the external nose.