Pterygopalatine Fossa

Deep-face crossroads: The pterygopalatine fossa (PPF) is a small inverted-pyramidal fat space between the posterior maxillary sinus and pterygoid process. Its multiple foramina and fissures connect the nasal cavity, orbit, palate, nasopharynx, infratemporal fossa, and middle cranial fossa—making it a key route for perineural and direct tumor spread.

Visual Reference

Pterygopalatine fossa boundaries, openings, and clinical pathways — Boundaries and Clinical PathwaysClick to enlarge

Pterygopalatine fossa CT anatomy and communications — CT Anatomy and CommunicationsClick to enlarge

Shape and Boundaries

Inverted pyramidThe broad superior PPF tapers inferiorly into the palatine canals.

Anterior: posterior wall of the maxillary sinus.
Posterior: pterygoid process and inferior greater wing of sphenoid.
Medial: perpendicular plate of the palatine bone.
Lateral: pterygomaxillary fissure.
Roof: sphenoid body and orbital process of palatine bone.
Floor: pyramidal process of palatine bone, tapering to the palatine canals.

Neurovascular Contents

Compact neurovascular hubNormally the PPF contains fat, small vessels, the pterygopalatine ganglion, and branches of CN V2.

Pterygopalatine ganglion and its branches.
Maxillary nerve (CN V2) entering through foramen rotundum.
Nerve of the pterygoid canal (vidian nerve).
Terminal maxillary artery and branches, including the descending palatine and sphenopalatine arteries.
Small emissary veins.

Normal imaging appearance

Preserved symmetric fat and smooth, non-enlarged foramina are reassuring. Mild enhancement can occur from small vessels.

Why the PPF Matters

Route of disease spreadLoss of PPF fat can be the first clue to direct invasion or perineural tumor spread.

Palatal disease can ascend along palatine nerves.
Cheek, maxillary sinus, and orbital disease can track along the infraorbital nerve.
Nasopharyngeal or nasal tumors can enter through the palatovaginal canal or sphenopalatine foramen.
Once in the PPF, tumor may reach the middle cranial fossa through foramen rotundum or the vidian canal.

Juvenile nasopharyngeal angiofibroma characteristically involves and expands the PPF.

Communications

Destination	Opening	Key transmitted structure
Nasal cavity	Sphenopalatine foramen	Sphenopalatine artery; nasal nerves
Infratemporal fossa	Pterygomaxillary fissure	Terminal maxillary artery branches
Orbit	Inferior orbital fissure	Infraorbital nerve and vessels
Middle cranial fossa	Foramen rotundum	Maxillary nerve (V2)
Petrous apex region	Vidian canal	Vidian nerve and vessels
Nasopharynx	Palatovaginal canal	Pharyngeal nerve and artery
Palate	Greater/lesser palatine canals	Palatine nerves and vessels

CT Technique and Findings

Use thin-section, submillimeter bone reconstructions to assess the walls, foramina, and canals.
Compare both fossae for asymmetry, fat replacement, widening, or osseous remodeling/destruction.
Trace foramen rotundum, vidian canal, palatine canals, inferior orbital fissure, and pterygomaxillary fissure.
Inspect the posterior maxillary sinus wall for bowing or erosion.

Angiofibroma pearl: An avid nasopharyngeal mass with PPF expansion and anterior bowing of the posterior maxillary wall produces the classic Holman–Miller sign.

MRI Technique and Findings

Noncontrast axial T1 is especially sensitive to replacement of normal high-signal PPF fat.
Acquire thin fat-suppressed postcontrast images through the deep face and skull base.
Evaluate V2 from the PPF through foramen rotundum to Meckel cave and cavernous sinus.
Evaluate the vidian nerve toward the foramen lacerum and the infraorbital nerve toward the orbit and cheek.
Dental hardware and adjacent sinus air may create susceptibility artifact.

Mild symmetric enhancement may be normal; asymmetric enhancement, expansion, or loss of fat is suspicious.

Reporting Checklist

PPF: preserved or replaced fat, enhancement, mass effect, and side-to-side asymmetry.

Neural pathways: V2/foramen rotundum, vidian canal, palatine canals, infraorbital nerve, and Meckel cave/cavernous sinus.

Direct extension: nasal cavity, nasopharynx, maxillary sinus, orbit, masticator space, palate, and skull base.

Bone and vessels: foraminal enlargement, remodeling versus destruction, maxillary artery involvement, and tumor vascularity.

High-yield statement

When PPF involvement is present, explicitly state whether disease reaches the skull base or intracranial compartment and identify the most proximal extent of perineural spread.