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.
RATIO AND PROPORTION. Ratio is the spoken language of arithmetic. It is how we relate quantities of the same kind. 6 people, for example, are half of 12 people. Half is the name of the ratio -- the relationship -- of 6 to 12. Most important, we will see that percents are ratios. In the language of percent, we say that 6 people are 50% of 12 people.