Lecture Notes: Meninges and Dural Partitions

Introduction

• Lecturer: Dr. Alsup
• Topic: Meninges and the specializations of the dura mater, focusing on dural partitions.

Meninges Overview

• Meninges are membranous coverings of the brain and spinal cord.
• Types of Meninges:
  • Dura Mater:
    • Most external, toughest, and thickest layer.
    • Pearly white or silver color.
    • Visible upon removal of the skull cap.
    • Associated with the dural venous sinuses.
  • Arachnoid Mater:
    • Thicker, can be dissected away from the brain.
  • Pia Mater:
    • Closely adhered to the brain, not easily dissected away.
    • Gives the brain a shiny appearance.

Dura Mater

• Brain dura mater has two layers:
  • Periosteal Layer (Endosteal): Visible without opening the dura.
  • Meningeal Layer: Forms dural partitions that protect the brain and create compartments.

Dural Partitions

• Formed by the meningeal layer of the dura mater.
• Functions:
  • Protects the brain.
  • Creates compartments in the cranial cavity.
• Types of Dural Partitions:
  1. Falx Cerebri:
     • Largest, sickle-shaped partition.
     • Runs down the longitudinal fissure between cerebral hemispheres.
     • Attaches to crista galli of ethmoid bone and internal occipital protuberance.
     • Houses the superior and inferior sagittal sinuses.
  2. Tentorium Cerebelli:
     • Second largest, transverse orientation.
     • Separates the occipital lobes from the cerebellum.
     • Features the tentorial notch for the midbrain.
  3. Diaphragma Sellae:
     • Covers the sella turcica of the sphenoid bone.
     • Forms a roof over the hypophyseal fossa with an aperture for the pituitary stalk.
     • Smallest and least dense.
  4. Falx Cerebelli:
     • Located between the cerebellar hemispheres.
     • Inferior to the tentorium cerebelli, near the foramen magnum.

Additional Details

• Arachnoid Trabeculae:
  • Located within the subarachnoid space.
  • Give a spider web-like appearance.
  • Contains vessels and cerebrospinal fluid (CSF).

Conclusion

• Review of cranial meninges and dural partitions completed.
• Encouragement to reach out with questions.

Reminder: Use these notes to review the key points discussed in the lecture and reach out to Dr. Alsup for clarification on any outstanding questions.