Lumbar puncture. Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to help diagnose diseases of the central nervous system, including the brain and spine.
2. ratio-the relation between things (or parts of things) with respect to their comparative quantity, magnitude, or degree; an inordinate proportion of the book is given over to quotations; a dry martini has a large proportion of gin. proportion.
quotient - the ratio of two quantities to be divided. proportion - the quotient obtained when the magnitude of a part is divided by the magnitude of the whole. ratio - the relative magnitudes of two quantities (usually expressed as a quotient) number - a concept of quantity involving zero and units; every number has a unique position in the sequence.