Pterygopalatine fossa

small pyramid-shaped space, lying behind the posterior wall of the maxillary sinus, anterior to the pterygoid process of the sphenoid bone, and medial to the vertical (perpendicular) plate of the palatine bone; laterally, it is open to the masticator space. The pterygopalatine fossa communicates with several surrounding spaces; it is open to the orbit via the inferior orbital fissure; it receives nerves via the foramen rotundum (maxillary nerve) and vidian canal (vidian nerve), leaving the fossa through the sphenopalatine foramen (exit to nasal cavity), major and minor palatine canals (exit to hard and soft palate) and infraorbital canal (main branch of maxillary nerve). In the pterygopalatine fossa, the internal maxillary artery divides into its terminal branches, supplying the nose and oral cavity. Also, see pterygopalatine fossa.

The neurovascular structures in the pterygopalatine fossa are surrounded by fat; this fat pad is easily seen on cross-sectional imaging and should appear symmetrical. Asymmetrical appearance of this fat is suspicious.

2. Pathology

Pathology primarily arising within the pterygopalatine fossa is rare; a neurogenic tumour head and neck is the entity most likely to be encountered.

The pterygopalatine fossa is more commonly involved by pathology arising in its immediate locality. Posterior spread of a maxillary cancer, or lateral spread of an angiofibroma are typical examples; from here, such lesions gain access to the other spaces communicating with the pterygopalatine fossa (see also sinonasal cavities cancer).

Being a crossroads of nerves, the pterygopalatine fossa is commonly involved by perineural tumour spread head and neck. From here, continued retrograde or anterograde perineural spread can occur; one possibility is spread along the maxillary nerve to the cavernous sinus and Meckel's cave, but also spread along the palatine nerves, posterior and superior alveolar nerves, or into the vidian canal, eventually reaching the facial nerve, is sometimes seen.

RH