Diagnostic Lumbar Puncture (Spinal Tap)


This is a way to get a sample of your cerebrospinal fluid (which we call "CSF"). That's the fluid that flows around your brain, spinal cord and spinal nerves. Testing this fluid will show signs of bleeding, infection or other problems.


To begin, you sit or lie on your side and bend forward to expose your lower back. The doctor gives you an injection to numb your skin.

Taking the Sample

Then, the doctor inserts a needle into your back. It's carefully pushed between two vertebral bones and into the dural sac (that's the sheath that protects your nerve roots). The needle won't come near your spinal cord, because your spinal cord ends at a level above where the needle is placed. Cerebrospinal fluid will slowly drip out of the needle. The doctor collects it in vials for study.

End of Procedure

When it's done, the needle is removed and your back is bandaged. Some people get a headache after the procedure. You may be asked to lie down for a short time to reduce your chance of getting one.