Pterygopalatine Fossa:
• Deep space ventral to orbit, deep to zygomatic arch
• Boundaries: Maxillary tuberosity (ant), pterygoid process (post), palatine perpendicular plate (medial)
• Contains: Maxillary nerve (V2), Maxillary artery, Pterygopalatine ganglion
• Clinical: Target for Peterson Eye Block (enucleation anesthesia)
• Entry: Foramen orbitorotundum

Temporal Fossa:
• Depression lateral to neurocranium, posterior to orbit
• Filled entirely by Temporalis muscle
• Displaced laterally by frontal sinus expansion in ox

Clinical Zones

The Pterygopalatine Fossa (Fossa pterygopalatina)

A deep, clinically critical space located ventral to the orbit and deep to the zygomatic arch.

Boundaries:

• Anterior: Maxillary tuberosity
• Posterior: Pterygoid process of sphenoid
• Medial: Perpendicular plate of palatine bone

Contents:

1. Maxillary Nerve (CN V2): Branches into the infraorbital, zygomatic, and pterygopalatine nerves.
2. Maxillary Artery: The terminal branch of the external carotid artery.
3. Pterygopalatine Ganglion: Parasympathetic ganglion.

Foramina Openings:

• Foramen Orbitorotundum: Entry of nerves from cranium.
• Maxillary Foramen: Entry to infraorbital canal.
• Sphenopalatine Foramen: To nasal cavity.
• Caudal Palatine Foramen: To hard palate.

Clinical Significance: This is the target site for the Peterson Eye Block, a local anesthesia technique used for enucleation (removal of the eye). The needle is directed into this fossa to block the maxillary and ophthalmic nerves.

The Temporal Fossa (Fossa temporalis)

The depression on the lateral side of the neurocranium, posterior to the orbit.

Boundaries: Medially by the parietal/frontal bones; laterally by the zygomatic arch.

Content: Filled entirely by the Temporalis muscle.

Comparative Note: Deep in the ox and dog; shallow in the horse. In the ox, it is displaced laterally by the frontal sinus expansion.