Answer :
When performing a spinal tap, the needle must be inserted to obtain CSF without damaging the spinal cord at the subarachnoid space between the third and fourth lumbar vertebrae.
Guidelines on how to perform a spinal tap
A spinal tap also called a lumbar puncture is technique used by a trained medical personnel to obtain a sample of the cerebrospinal fluid ( CSF).
This is performed using a highly aseptic measures and procedure. A local anaesthetic is injected at the lower back before the needle is inserted at the subarachnoid space between the third and fourth lumbar vertebrae.
The spinal cord ends at the first and second lumbar vertebrae.
Therefore, the insertion of the hollow needle at the subarachnoid space between the third and fourth lumbar vertebrae is the safest.
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