Lumbar Puncture C15327 Lumbar Puncture spinal tap A procedure in which a thin needle called a spinal needle is put into the lower part of the spinal column to collect cerebrospinal fluid or to give drugs. Lumbar Puncture LP lumbar puncture An invasive procedure in which a hollow needle is introduced through an intervertebral space in the lower back to access the subarachnoid space in order to sample cerebrospinal fluid or to administer medication. Diagnostic Procedure Lumbar_Puncture Spinal Tap C0037943 specimen collection