Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page: //medlineplus.gov/ency/imagepages/9587.htm

Lumbar puncture

Lumbar puncture

Overview

Cerebral spinal fluid (CSF) is a clear fluid that circulates in the space surrounding the spinal cord and brain. CSF protects the brain and spinal cord from injury by acting like a liquid cushion. CSF is usually obtained through a lumbar puncture (spinal tap). During the procedure, a needle is inserted usually between the 3rd and 4th lumbar vertebrae and the CSF fluid is collected for testing.

Review Date 7/1/2023

Updated by: Jason Levy, MD, FSIR, Northside Radiology Associates, Atlanta, GA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.