Would you withdraw csf if the needle were accidentally inserted into the epidural space instead of the subarachnoid

space? why or why not?

No. You would not withdraw CSF if the needle is in the epidural space.

Explanation: There are 3 spaces that cover the spinal cord, which are epidural, subdural and subarachnoid spaces. The epidural space is the outer most space while the subarachnoid space is the inner most space. CSF flows from the brain where it is produced to the spinal cord. In the spinal cord it flows only in the subarachnoid space. Thus you would not be able to withdraw CSF if the needle is in the epidural space.