A lumbar puncture, also known as a spinal tap, is a medical procedure used to collect cerebrospinal fluid (CSF) from the lower back. This fluid surrounds the brain and spinal cord, providing important information about neurological conditions. The procedure involves inserting a thin needle into the lumbar region of the spine, typically between the third and fourth lumbar vertebrae. During the procedure, the patient usually lies on their side or sits up, and local anesthesia is applied to minimize discomfort. The collected CSF can be analyzed for various conditions, including infections, bleeding, and multiple sclerosis. It is a safe procedure, though some risks, such as headache or infection, may occur.