Lumbar puncture, also called a spinal tap, is the procedure doctors use to obtain a sample of cerebrospinal fluid (the liquid that surrounds the brain and spinal cord) for tests. Cerebrospinal fluid (CSF) is formed in special areas of the brain called ventricles. It flows down from the ventricles into the area around the spinal cord. CSF is usually clear and contains small amounts of proteins and glucose (sugar).
The October 25, 2006, issue of JAMA includes an article about lumbar puncture to diagnose meningitis. This Patient Page is based on one previously published in the October 23/30, 2002, issue of JAMA.