Samples of CSF for diagnostic purposes are normally obtained by placing the tip of a needle into the subarachnoid space, usually between the third and fourth lumbar vertebrae.
CSF (Cerebrospinal fluid) is made up of tissue that lines the hollow spaces in the brain, and that hollow space is known as ventricles. This fluid flows in and around the human brain and spinal cord in order to provide cushion them from injury and provide nutrients.
Subarachnoid space consists of the cerebrospinal fluid (CSF), major blood vessels, and cisterns. The main function of the subarachnoid space is to protect CSF which cushions the brain and the spinal cord, and It also provides nutrients and removes waste.
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