Arachnoid Mater Flashcards

Examine the spinal arachnoid mater, its meningeal relationships, subarachnoid space, cerebrospinal fluid, and clinical anatomy.

Card 1 of 23Question

What is the arachnoid mater?

A thin, avascular meningeal membrane located between the dura mater and pia mater.

In This Section

1. What is the arachnoid mater?

A thin, avascular meningeal membrane located between the dura mater and pia mater.

2. Which meningeal layer lies immediately superficial to the spinal arachnoid mater?

The dura mater.

3. Which meningeal layer lies deep to the spinal arachnoid mater?

The pia mater.

4. To which category of meninges does the arachnoid mater belong?

The leptomeninges, together with the pia mater.

5. What are the two principal structural components of the arachnoid mater?

An outer arachnoid barrier cell layer and an inner trabecular layer.

6. What type of cellular junctions characterize the arachnoid barrier layer?

Tight junctions that restrict movement of substances across the membrane.

7. What are arachnoid trabeculae?

Delicate connective tissue strands extending between the arachnoid mater and pia mater.

8. What is the subarachnoid space?

The fluid-filled space between the arachnoid mater and pia mater.

9. Which fluid occupies the spinal subarachnoid space?

Cerebrospinal fluid (CSF).

10. Which neural structures pass through the spinal subarachnoid space?

Spinal nerve roots, including the roots forming the cauda equina.

11. Does the spinal arachnoid mater closely follow the contours of the spinal cord?

No. It forms a relatively loose tubular covering around the spinal cord.

12. What is the subdural space in relation to the arachnoid mater?

A potential space at the dura-arachnoid interface that can open through tissue separation.

13. At approximately which vertebral level does the spinal arachnoid sac terminate in adults?

The second sacral vertebral level (S2).

14. What is the lumbar cistern?

The enlarged subarachnoid space below the conus medullaris and above the termination of the dural sac.

15. Which structures are contained within the lumbar cistern?

Cerebrospinal fluid, the cauda equina, and the filum terminale internum.

16. At approximately which vertebral level does the adult spinal cord usually terminate?

Near the L1 to L2 vertebral level.

17. Which intervertebral spaces are commonly used for lumbar puncture?

The L3-L4 or L4-L5 intervertebral spaces.

18. Which meningeal layers must a lumbar puncture needle penetrate to reach cerebrospinal fluid?

The spinal dura mater and arachnoid mater.

19. Why is lumbar puncture generally performed below the termination of the spinal cord?

To reduce the risk of direct spinal cord injury while accessing the lumbar cistern.

20. What is the role of the spinal subarachnoid space in cerebrospinal fluid circulation?

It provides a continuous pathway for cerebrospinal fluid around the spinal cord.

21. What embryological cell population contributes to the development of the spinal arachnoid mater?

Mesenchymal cells derived predominantly from mesoderm in the spinal region.

22. What is spinal arachnoiditis?

Inflammation of the spinal arachnoid that may cause fibrosis and adhesion of nerve roots.

23. What is a spinal arachnoid cyst?

A cerebrospinal fluid-filled lesion associated with the arachnoid membrane that may compress the spinal cord or nerve roots.