A lumbar puncture, commonly referred to as a spinal puncture, is a procedure used to collect fluid samples from the spinal cord or cerebrospinal fluid (CSF). This helps measure fluid pressure and diagnose various health conditions. It is particularly useful for identifying meningitis (inflammation of the membranes surrounding the brain and spinal cord), encephalitis (brain inflammation caused by a virus), and certain cancers such as Reye syndrome and myelitis (inflammation of the spinal cord or bone marrow).

How the lumbar puncture procedure unfolds.

1. Positioning: The patient is generally asked to lie on their side with their knees pulled towards their chest, or they may sit and lean forward. This position helps widen the spaces between the lumbar vertebrae, making it easier and safer to insert the needle into the spinal canal.
2. Preparation: The site of insertion, usually between the third and fourth lumbar vertebrae, is cleaned and sterilized to minimize the risk of infection. A local anesthetic is then administered to numb the skin and deeper tissues, helping to reduce discomfort during the procedure.
3. Needle Insertion: After the area is numb, a thin, hollow needle is carefully inserted between the vertebrae into the spinal canal. The physician will advance the needle through the spinal ligaments until it reaches the subarachnoid space, where the CSF circulates around the spinal cord and brain.
4. CSF Collection: Once the needle is properly positioned in the subarachnoid space, a small amount of CSF is withdrawn into sterile tubes. The CSF pressure may be measured, and the fluid is sent to a laboratory for further analysis. After the procedure is completed, the needle is removed, and a small bandage is applied to the puncture site.