Anatomy Lecture: Cavernous Sinus

Introduction to Dural Venous Sinuses

• Dural Venous Sinuses: Specialized venous channels found within the cranial cavity.
• Dura Mater: Composed of two layers:
  • Periosteal Layer (Endosteum): Faithfully attached to the inner cranial bones.
  • Meningeal Layer: Less faithful, can separate and form infoldings, creating spaces between layers.
• Function: These infoldings and separations form dural venous sinuses, filled with venous blood, lined by endothelium.
• Characteristics: Valve-less, allowing bidirectional blood flow influenced by local pressure changes.

Cavernous Sinus

• Location: Situated in the middle cranial fossa, lateral to the sella turcica and the body of the sphenoid bone, surrounding the pituitary gland.
• Dimensions: Approximately 2 cm long and 1 cm wide.
• Structure:
  • Created by separation of the dura mater's layers.
  • Contains a network of endothelium-lined venous channels within, appearing like trabecular structures or caverns.
  • It extends anteriorly to the superior orbital fissure and posteriorly to the tip of the petrous part of the temporal bone.

Formation

• Endosteal Layer: Remains attached to the bone, forming the floor and part of the medial wall.
• Meningeal Layer: Separates and forms the roof and lateral wall, also forming part of the medial wall.
  • Diaphragma Sellae: Meningeal fold covering the pituitary gland with an aperture for the pituitary stalk.

Function and Importance

• Cavernous Sinus: Called 'cavernous' due to its interior architecture of multiple interconnected venous channels.
• Unique Feature: Composed of multiple small spaces, resembling small caves or caverns, providing a conduit for venous blood.

Clinical Relevance

• Understanding the structure and location of the cavernous sinus is crucial due to its proximity to several cranial nerves and the internal carotid artery, making it a clinically significant structure.

This lecture covered the fundamental concepts of dural venous sinuses, focusing specifically on the anatomy, structure, and function of the cavernous sinus.