Subarachnoid Space Flashcards

Examine the spinal subarachnoid space, its meningeal boundaries, cerebrospinal fluid, lumbar cistern, nerve roots, and clinical anatomy.

Card 1 of 24Question

What is the subarachnoid space?

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

In This Section

1. What is the subarachnoid space?

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

2. Which meningeal layer forms the outer boundary of the spinal subarachnoid space?

The arachnoid mater.

3. Which meningeal layer forms the inner boundary of the spinal subarachnoid space?

The pia mater.

4. What are the principal contents of the spinal subarachnoid space?

Cerebrospinal fluid, spinal nerve roots, blood vessels, and arachnoid trabeculae.

5. What is the main protective function of cerebrospinal fluid within the subarachnoid space?

It provides buoyancy and mechanical cushioning for the spinal cord.

6. How does the spinal subarachnoid space communicate with the cranial subarachnoid space?

The two spaces are continuous through the foramen magnum.

7. At approximately which vertebral level does the spinal subarachnoid space terminate in adults?

The second sacral vertebral level (S2).

8. What is the lumbar cistern?

The enlarged portion of the spinal subarachnoid space below the conus medullaris.

9. Between which vertebral levels does the lumbar cistern typically extend in adults?

Approximately L1-L2 to S2.

10. Which spinal nerve roots descend through the lumbar cistern?

The lumbar, sacral, and coccygeal nerve roots forming the cauda equina.

11. Which pial structure extends through the lumbar cistern from the conus medullaris?

The filum terminale internum.

12. What are arachnoid trabeculae?

Delicate connective tissue strands connecting the arachnoid mater to the pia mater.

13. What is the relationship of the denticulate ligaments to the spinal subarachnoid space?

They extend laterally through it from the pia mater to the dura mater.

14. Which major longitudinal arteries travel within the spinal subarachnoid space?

The anterior spinal artery and paired posterior spinal arteries.

15. What is the relationship between the spinal subarachnoid space and the central canal?

They are distinct cerebrospinal fluid compartments; the central canal lies within the spinal cord.

16. Which openings allow cerebrospinal fluid to enter the cranial subarachnoid space from the fourth ventricle?

The median aperture of Magendie and paired lateral apertures of Luschka.

17. Which intervertebral spaces are commonly selected for lumbar puncture in adults?

The L3-L4 or L4-L5 intervertebral spaces.

18. Why is the lumbar cistern a preferred location for cerebrospinal fluid sampling?

It lies below the usual termination of the adult spinal cord, reducing the risk of direct cord injury.

19. Which meningeal membranes must a lumbar puncture needle penetrate to enter the subarachnoid space?

The dura mater and arachnoid mater.

20. Which anatomical space receives local anesthetic during spinal anesthesia?

The subarachnoid space, where the anesthetic mixes with cerebrospinal fluid.

21. How does spinal anesthesia differ anatomically from epidural anesthesia?

Spinal anesthesia enters the subarachnoid space, while epidural anesthesia targets the space outside the dura mater.

22. What is a spinal subarachnoid hemorrhage?

Bleeding into the cerebrospinal fluid-filled space surrounding the spinal cord.

23. How can adhesive arachnoiditis affect the spinal subarachnoid space?

Inflammation and fibrosis may cause nerve root adhesions and disrupt cerebrospinal fluid circulation.

24. How can an expanding spinal arachnoid cyst affect adjacent neural structures?

It may compress the spinal cord or nerve roots and alter local cerebrospinal fluid flow.