Meninges - SEER Training

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3. Brain & Other Nervous System Tumors
4. Brain & CNS Tumors
5. Anatomy
6. Meninges

• Brain & Other Nervous System Tumors
  • Non-malignant Brain Tumors
    • History of CNS Tumor Surveillance & Registration
      • BTWG Recommendations
      • Public Law 107-260
    • Reportable Cases
    • Casefinding
    • Anticipated Impact on Registries
    • Review: Non-malignant Brain Tumors
  • Brain & CNS Tumors
    • Signs & Symptoms
    • Anatomy
      • Neurons & Glial Cells
      • Brain
      • Meninges
      • Spinal Cord
      • Cranial Nerves
      • Pineal and Pituitary Glands
    • Abstracting, Coding, and Staging
      • Topographic Sites
      • Histological Types
      • Grading
      • Staging
      • Multiple Primaries
      • Malignant Transformation
      • Coding Sequence Numbers
      • Date of Diagnosis
      • Standard Treatment & Surgery Codes
      • Other Treatments
      • Review
• Module (Breast Cancer)

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There are three layers of meninges around the brain and spinal cord. The outer layer, the dura mater, is tough, white fibrous connective tissue. The middle layer of meninges is arachnoid, a thin layer resembling a cobweb with numerous threadlike strands attaching it to the innermost layer. The space under the arachnoid, the subarachnoid space, is filled with cerebrospinal fluid and contains blood vessels. The pia mater is the innermost layer of meninges. This thin, delicate membrane is tightly bound to the surface of the brain and spinal cord and cannot be dissected away without damaging the surface.

Meningiomas are tumors of the nerve tissue covering the brain and spinal cord. Although meningiomas are unlikely to spread, physicians often treat them as though they were malignant because symptoms may develop when a tumor applies pressure to the brain.

For more information about anatomy of brain and CNS, go to the Nervous System section of the Anatomy & Physiology module on this Website.

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Suggested Citation

SEER Training Modules: Meninges. U.S. National Institutes of Health, National Cancer Institute. Cited 02 January 2026. Available from: https://training.seer.cancer.gov.

Glossary Term