Definition of "lumbar puncture" []

• The insertion of a hollow needle beneath the arachnoid membrane of the spinal cord in the lumbar region to withdraw cerebrospinal fluid for diagnostic purposes or to administer medication. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "During the spinal tap, or lumbar puncture, a terrible medical mishap occurred: the lumbar puncture was made into what physicians refer to as the danger zone—the cauda equina—a group of nerve roots that send and receive messages to and from the lower abdominal organs and down into the legs."
• "Nevertheless, over a four-day period, Matthew was subjected to “a colonoscopy, a barium meal and follow-through, an MRI scan of his brain, a lumbar puncture . . . an EEG and other neurophysiological tests, and a variety of blood and urine tests.”"