TY - CHAP M1 - Book, Section TI - Lumbar Puncture A1 - Killu, Claude A1 - J. Ault, Mark A2 - McKean, Sylvia C. A2 - Ross, John J. A2 - Dressler, Daniel D. A2 - Scheurer, Danielle B. PY - 2017 T2 - Principles and Practice of Hospital Medicine, 2e AB - Lumbar puncture (LP) is performed to sample the cerebrospinal fluid (CSF) surrounding the brain and spinal cord. The majority of the CSF is in the subarachnoid space, where the arachnoid membranes bridge the sulci of the brain, in the basal cisterns and around the spinal cord. Cerebrospinal fluid moves within the ventricles and subarachnoid spaces under the influence of hydrostatic pressure generated by the production of CSF by the choroid plexus of the lateral third and fourth ventricles. The volume of CSF in humans is 140 to 150 mL of which only 30 to 40 mL is actually in the ventricular system, with a production rate of 21 mL/h. The turnover rate of total CSF is about 5 hours for an average sized human. Cerebrospinal fluid cushions the brain, regulates brain extracellular fluid, allows for distribution of neuroactive substances, and collects the waste products produced by the brain. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1137613138 ER -