For a lumbar
puncture, you lie on your side with your knees drawn up toward your chest. This
position helps widen the spaces between the bones of the lower spine so that
the needle can be inserted more easily. A numbing medicine (local anesthetic)
is put in the skin. Then a long, thin needle is put in the spinal canal to collect a sample of cerebrospinal fluid (CSF). Your
doctor may need to move to another area of your spine if it is hard to get to
the spinal fluid.
The color, blood cell counts, and amounts of protein, glucose, and other substances are measured in the CSF sample. Some of the sample may be put into a special culture cup to see if any bacteria or fungi grow. The pressure of the CSF also is measured during the procedure.
How this information was developed to help you make better health decisions.