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.
proportion. n. 1. the relationship between different things or parts with respect to comparative size, number, or degree; relative magnitude or extent; ratio. 2. the correct or desirable relationship between parts of a whole; balance or symmetry. 3. a part considered with respect to the whole.