|med insertion of a hollow needle into the lower region of the spinal cord to withdraw cerebrospinal fluid, introduce drugs, etc|
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.
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.