Pterygopalatine fossa

Overview

The pterygopalatine fossa is a cone-shaped fossa on both sides of the skull that serves as a major distribution centre for parasympathetic innervation and vascular supply of deep facial structures. It is located between the pterygoid process and maxillary tuberosity (near the apex of the orbit).

Borders

• Anterior – Posterior wall of the maxillary sinus
• Posterior – Pterygoid process of the sphenoid bone
• Inferior – Palatine bone and palatine canals
• Superior – Inferior orbital fissure of the eye
• Medial – Perpendicular plate of the palatine bone
• Lateral – Pterygomaxillary fissure

Contents

Nerves

• Maxillary branch of trigeminal nerve (CN V₂) – Enters from middle cranial fossa via foramen rotundum
• Pterygopalatine ganglion – suspended by the nerve roots from the maxillary nerve

 Vessels

• Maxillary artery – the pterygopalatine portion (third part) of the maxillary artery enters via the pterygomaxillary fissure, loops within the fossa and gives rise to terminal branches;
  • Infraorbital artery – lacrimal gland and muscles of eye via inferior orbital fissure
  • Sphenopalatine artery – nasal cavity via sphenopalatine foramen
  • Pharyngeal artery – nasal cavity via pharyngeal canal
  • Descending palatine artery – greater and lesser palatine arteries (hard and soft palates) via greater palatine canal
  • Posterior superior alveolar artery – to gingiva and teeth via pterygomaxillary fissure
  • Artery of pterygoid canal – middle cranial fossa via pterygoid canal.

Communications & Relations

Posteriorly

• Foramen rotundum (posterosuperiorly)
  • Communicates with the middle cranial fossa – Meckel’s cave and cavernous sinus
  • Transmits the maxillary division of trigeminal nerve
• Pterygoid (Vidian) canal (posteroinferiorly)
  • Communicates with the middle cranial fossa and foramen lacerum
  • Transmits the vidian nerve, vidian artery and vidian vein
• Palatovaginal (pharyngeal canal) (posteromedially)
  • Communicates with the nasopharynx
  • Transmits the pharyngeal nerve and pharyngeal branch of the maxillary artery

Anteriorly

• Inferior orbital fissure
  • Communicates with the orbit
  • Transmits the infraorbital artery

Medially

• Sphenopalatine foramen
  • Communicates with the nasal cavity
  • Transmits the sphenopalatine artery, nasopalatine nerve and posterior superior nasal nerves

Laterally

• Pterygomaxillary fissure
  • A triangular-shaped opening located on the medial aspect of the infratemporal fossa
  • Transmits the posterior superior alveolar nerve and terminal branches of the maxillary artery

Inferiorly

• Greater palatine canal (pterygopalatine)
  • Communicates with the oral cavity and lesser palatine canals

Relations

Through 8 bony canals or foramina, the fossa communicates with the following structures:

• medially connected to nasal cavity (superior meatus) via sphenopalatine foramen, transmits sphenopalatine artery and vein and nasaopalatine nerve.
• inferiorly the less and greater palatine canals communicate with the oral cavity.
• anterosuperiorly connected to orbital apex via posteromedial aspect of infraorbital fissure.
• laterally continuous with infratemporal fossa via pterygomaxillary fissure (transmits posterior superior alveolar artery and terminal part of maxillary artery).
• posteriorly:
  • foramen rotundum – above and lateral to pterygoid canal, connects pterygopalatine fossa with middle cranial fossa, transmits the maxillary nerve.
  • pterygoid or vidian canal – lies between roots of medial and lateral pterygoid plates connecting pterygopalatine fossa with with foramen lacerum.
  • pharyngeal or palatinovaginal canal – formed by junction of processus vaginalis of sphenoid and sphenoidal process of nasophraynx with the pterygopalatine fossa, transmitting pharyngeal branch of maxillary nerve and artery.

Clinical relevance

• Potential conduit for dissemination of disease process to contiguous structures.