• This region involves the dissection of a very small area containing very small structures.  Much care will be necessary to complete the dissection necessary.  It may be beneficial to examine a prosection of the area to gain insight as to the area and size of the structures you are looking for as well as what a completed dissection looks like.

    1.  Find the pterygpalatine fossa on your model skull and compare its position to the nasal cavity, orbit, and infratemporal fossa.  With a pipecleaner or probe, insert it into the infratemporal region and note that the probe can be seen through the inferior orbital fissure of the orbit.  It will be the goal of this dissection to expose the pterygopalatine fossa region from the lateral nasal cavity wall.
    2.  Remove the posterior portion of the inferior and middle nasal concha to the ethmoidal bulla.  Remove the mucosa of the lateral nasal wall from the ethmoidal bulla to the region inferior to the sphenoid sinus.  In doing so, the perpendicular plate of the palatine bone is exposed.
    3.  Identify the sphenopalatine foramen at the superior posterior portion of the nasal cavity.  Note that many of the vessels and nerves of the nasal cavity exit the pterygopalatine fossa to the nasal cavity via the sphenopalatine foramen.
    4. With a blunt probe, remove the bone inferior to the sphenopalatine foramen (perpendicular plate of the palatine bone).  The bone here is thin and should break away easily; little pressure will be necessary.
    5.  With the bone removed, the greater and lesser palatine nerves and vessels should be identified.  These structures travel inferiorly to the oral cavity conveying sensory information from the hard and soft palates.  The greater palatine nerve lies anterior to the lesser palatine nerve.
    6.  Follow the palatine nerves superiorly to the region of the pterygopalatine ganglion which will appear as a nondescript junction of nerves.  Additional bone may need to be removed to expose this region.  This ganglion is a collection of postsynaptic parasympathetic nerve cell bodies.
    7.  With a blunt probe, locate the pterygoid canal at the posterior edge of the pterygopalatine fossa, running in the floor of the sphenoid sinus.  In this canal runs the vidian nerve; carrying presynaptic parasympathetic and postsynaptic sympathetic fibers to the ganglion.  Carefully remove the bone with a hammer and chisel with the probe in the canal to protect the nerve and serve as a depth gauge.
    8.  Superior to the ganglion, identify the maxillary nerve (V2 of CN V) with its communicating branches to the ganglion.  Descending from V2 and passing by the ganglion is the smaller pharyngeal nerve.  This nerve enters a small canal on the posterior wall of the fossa and descends to the roof of the nasopharynx.
    9.  V2 continues past the fossa crossing the infraorbital foramen and enters the infraorbital foramen becoming the infraorbital nerve.  With a good dissection, one can follow V2 before it enters the infraorbital canal by carefully removing the mucosa and bone of the maxillary sinus.  Identify the posterior superior alveolar nerves which leave V2 before the nerve enters the infraorbital canal.  Sometimes, branches of the middle and anterior superior alveolar nerves and vessels may be seen travelling withing tiny canals in the wall of the maxillary sinus.
   10.  The maxillary artery can also be seen deep to the fossa and maxillary sinus giving off branches to the palate and nasal cavity.  If any arteries are visible, identify them.

Borders of the Fossa
Palatine Nerves
Pterygopalatine Ganglion
Vidian Nerve
Maxillary Nerve V2
Lateral Nasal Wall and Nasal Septum
Pterygopalatine Fossa Structures List