RT Book, Section A1 Waxman, Stephen G. SR Print(0) ID 1186190597 T1 Cerebrospinal Fluid Examination T2 Clinical Neuroanatomy, 29e YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN 9781260452358 LK accessmedicine.mhmedical.com/content.aspx?aid=1186190597 RD 2024/03/29 AB Analysis of the cerebrospinal fluid (CSF) can provide useful diagnostic information. As noted in Chapter 6, CSF is usually obtained from the lumbar subarachnoid space via a spinal tap, also called a lumbar puncture. Usually, this is carried out at the L3–4 or L4–5 interspace, with the patient in the lateral decubitus position. In some cases, it is easier to perform lumbar puncture with the patient in a sitting position. Because the spinal cord in adults ends at the L1–2 level, lumbar puncture can be performed below that level (and above the sacrum) without injuring the cord.