Question

In the adult spinal cord, to which vertebrae does the subarachnoid space extend?

1) S1
2) S2
3) S3
4) S4

Answer 1

The subarachnoid space extends from the first or second lumbar vertebrae (L1 or L2) down to the sacrum.

Step-by-step explanation:

The subarachnoid space is a space between the arachnoid mater and the pia mater that surrounds the spinal cord. It is filled with cerebrospinal fluid (CSF), which protects and cushions the spinal cord. The subarachnoid space extends from the first or second lumbar vertebrae (L1 or L2) down to the sacrum. Therefore, the correct answer is option 3) S3.