| Medicine/Medical. puncture into the arachnoid membrane of the spinal cord, in the lumbar region, and withdrawal of spinal fluid, performed for diagnosis of the fluid, injection of dye for imaging, or administration of anesthesia or medication. |
lumbar puncture n.
Puncture into the subarachnoid space of the lumbar region for diagnostic or therapeutic purposes. Also called rachicentesis, rachiocentesis, spinal puncture, spinal tap.
spinal tap n.
See lumbar puncture.
| 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. |
| spinal tap
See lumbar puncture. |
spinal tap
direct aspiration (fluid withdrawal) of cerebrospinal fluid (CSF) through a hollow needle. The needle is inserted in the lower back, usually between the third and fourth lumbar vertebrae, into the subarachnoid space of the spinal cord where the CSF is located. Lumbar puncture is generally performed to obtain pressure measurements and to withdraw CSF in order to secure a sample of CSF for cellular, chemical, and bacteriologic examination; to administer spinal anesthetics or antibiotics; to inject air or a radiopaque or water-soluble contrast medium substance for myelography; or to inject a radioactive substance to assist in the diagnosis of CSF leak or hydrocephalus.
Learn more about spinal tap with a free trial on Britannica.com.
