Pterygoid processes

The pterygoid processes or pterygoid plates are paired posteroinferior projections of the sphenoid bone.

Gross anatomy

Each pterygoid process projects inferiorly from the junction of the body and greater wing of the sphenoid bone and bifurcates into a medial pterygoid plate and a lateral pterygoid plate. At the inferior tip of the medial pterygoid plate is the small hook-shaped process, the pterygoid hamulus.

Relations

The spaces separated the medial and lateral plate are pterygoid fissure inferiorly and pterygoid fossa posterosuperiorly. The lateral aspect of the lateral pterygoid plate forms the medial wall of the infratemporal fossa. The root of the pterygoid process forms the posterior wall of the pterygopalatine fossa. The anterior opening of the pterygoid canal also sits on the anterior aspect of the root of the pterygoid process.

The pterygoid hamulus has two important relations, related to its function:

• tensor veli palatini tendon passes immediately behind it
• superior attachment of the pterygomandibular raphe

Attachments

Musculotendinous

• lateral pterygoid muscle: the lower part of the lateral pterygoid is attached to the lateral aspect of the lateral pterygoid plate
• medial pterygoid muscle: medial aspect of the lateral pterygoid plate
• superior pharyngeal constrictor: inferior end of the medial pterygoid plate

Related pathology

Pterygoid plates are important in diagnosing midface fractures. In Le Fort classification of midface fracture, the involvement of pterygoid plates is necessary to confirm the diagnosis.

History and etymology

"Pterygoid" derives from the classical Greek words "πτερον" (wing) and "είδος" (-like) .