Spinal arachnoid mater

The spinal arachnoid mater is a thin, delicate and avascular connective tissue membrane which forms the middle layer of the meninges and covers the spinal cord loosely 1. It becomes continuous with the cerebral arachnoid mater as it traverses the foramen magnum and terminates at the S2 vertebral level 2. It is in direct contact but does not adhere to the inner aspect of the dura mater, from which it is separated by a thin film of lymph. The arachnoid mater sends many wispy web-like processes or trabeculae across the cerebrospinal fluid-filled subarachnoid space to the underlying pia mater 3. These form an incomplete posterior median septum in the posterior midline of the spinal cord 1. 

Related pathology

Spinal anatomy
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Article information

rID: 47567
Section: Anatomy
Tag: cases
Synonyms or Alternate Spellings:

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