Meninges

(Redirected from Leptomeningeal)
Jump to navigation Jump to search

Template:Infobox Anatomy

WikiDoc Resources for Meninges

Articles

Most recent articles on Meninges

Most cited articles on Meninges

Review articles on Meninges

Articles on Meninges in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Meninges

Images of Meninges

Photos of Meninges

Podcasts & MP3s on Meninges

Videos on Meninges

Evidence Based Medicine

Cochrane Collaboration on Meninges

Bandolier on Meninges

TRIP on Meninges

Clinical Trials

Ongoing Trials on Meninges at Clinical Trials.gov

Trial results on Meninges

Clinical Trials on Meninges at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Meninges

NICE Guidance on Meninges

NHS PRODIGY Guidance

FDA on Meninges

CDC on Meninges

Books

Books on Meninges

News

Meninges in the news

Be alerted to news on Meninges

News trends on Meninges

Commentary

Blogs on Meninges

Definitions

Definitions of Meninges

Patient Resources / Community

Patient resources on Meninges

Discussion groups on Meninges

Patient Handouts on Meninges

Directions to Hospitals Treating Meninges

Risk calculators and risk factors for Meninges

Healthcare Provider Resources

Symptoms of Meninges

Causes & Risk Factors for Meninges

Diagnostic studies for Meninges

Treatment of Meninges

Continuing Medical Education (CME)

CME Programs on Meninges

International

Meninges en Espanol

Meninges en Francais

Business

Meninges in the Marketplace

Patents on Meninges

Experimental / Informatics

List of terms related to Meninges

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Overview

The meninges (singular meninx) is the system of membranes which envelop the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.

Anatomy

Pia mater

The pia or pia mater is a very delicate membrane. It is attached to (nearest) the brain or the spinal cord. As such it follows all the minor contours of the brain (gyri and sulci). The pia mater is the meningeal envelope which firmly adheres to the surface of the brain and spinal cord. It is a very thin membrane composed of fibrous tissue covered on its outer surface by a sheet of flat cells thought to be impermeable to fluid. The pia mater is pierced by blood vessels which travel to the brain and spinal cord, and its capillaries are responsible for nourishing the brain.

Arachnoid mater

The middle element of the meninges is the arachnoid mater, so named because of its spider web-like appearance. It provides a cushioning effect for the central nervous system. The arachnoid mater exists as a thin, transparent membrane. It is composed of fibrous tissue and, like the pia mater, is covered by flat cells also thought to be impermeable to fluid. The arachnoid does not follow the convolutions of the surface of the brain and so looks like a loosely fitting sac. In the region of the brain, particularly, a large number of fine filaments called arachnoid trabeculae pass from the arachnoid through the subarachnoid space to blend with the tissue of the pia mater.

The arachnoid and pia mater are sometimes together called the leptomeninges.

Dura mater

The dura mater (also rarely called meninx fibrosa, or pachymeninx) is a thick, durable membrane, closest to the skull. It contains larger blood vessels which split into the capilliaries in the pia mater. It is composed of dense fibrous tissue, and its inner surface is covered by flattened cells like those present on the surfaces of the pia mater and arachnoid. The dura mater is a sac which envelops the arachnoid and has been modified to serve several functions. The dura mater surrounds and supports the large venous channels (dural sinuses) carrying blood from the brain toward the heart.

Spaces

The subarachnoid space is the space which normally exists between the arachnoid and the pia mater, which is filled with cerebrospinal fluid.

Normally, the dura mater is attached to the skull in the head, or to the bones of the vertebral canal in the spinal cord. The arachnoid is attached to the dura mater, and the pia mater is attached to the central nervous system tissue. When the dura mater and the arachnoid separate through injury or illness, the space between them is the subdural space.

Pathology

There are three types of hemorrhage involving the meninges:[1]

Other medical conditions which affect the meninges include meningitis (usually from fungal, bacterial, or viral infection) and meningiomas arising from the meninges or from tumors formed elsewhere in the body which metastasize to the meninges.

Additional images

References

  1. Orlando Regional Healthcare, Education and Development. 2004. "Overview of Adult Traumatic Brain Injuries." Retrieved on September 6, 2007.

Template:Meninges

de:Hirnhäute he:קרומי המוח it:Meningi la:Meninges no:Hjernehinne sv:Hjärnhinna

Template:WH Template:WS