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Spinal tap

Overview of spinal tap

A spinal tap is a procedure to collect a sample of cerebrospinal fluid (CSF). CSF is a clear fluid that surrounds and protects your brain and spinal cord. Your body maintains CSF at a certain pressure, which allows it to buffer the brain and spinal cord from damage.  

The medical term for a spinal tap is “lumbar puncture” because the CSF is taken from the lumbar or lower back area of the spine. This is the preferred location for a spinal tap because CSF is most accessible from the lower back area, and the risk of needle injury to the spinal cord itself is the lowest in this area.  

At Dignity Health, our neurologists, anesthesiologists, and specialized nurses and physician assistants perform spinal taps. You can trust our medical experts to provide compassionate care during neurosurgery or any procedure. Find a Dignity Health location near you today. 

Why it’s necessary

Doctors perform a spinal tap to measure pressures within the CSF and collect a sample for further testing. Spinal taps help doctors investigate several conditions, including: 

  • Brain bleeding due to brain injury or other conditions, such as a bleeding aneurysm or bleeding disorder. 
  • Infections of the brain or spinal cord. 
  • Rise in intracranial pressure, which can be caused by increased CSF pressure. 
  • Infections such as meningitis or encephalitis. 
  • Cancers of the brain or spinal cord. 
  • Inflammatory conditions in the nervous system, including multiple sclerosis and Guillain-Barre syndrome. 

Doctors sometimes also perform lumbar punctures to deliver medications directly to the spinal cord area. 

Common conditions treated with spinal tap

Spinal taps are primarily used as a diagnostic tool. The CSF that is collected through this procedure is sent to a lab and evaluated on a number of different criteria to help your doctor come to a diagnosis.  

In addition to testing, spinal taps may be used to deliver medications. Commonly, anesthetics and chemotherapy drugs are administered via spinal tap. So, while it is not a treatment for cancer, it can sometimes be used in administering treatment. Doctors may also inject dye or radioactive substances into the cerebrospinal fluid. This helps with diagnostic imaging in some cases. 


There are some risks to getting a spinal tap, including: 

  • Infection from the needle 
  • Discomfort during the actual test 
  • Bleeding into the spinal canal 
  • Bleeding around the brain 
  • Headache lasting up to a few days after the test 
  • Allergic reaction to the anesthetic 
  • Damage to the nerves of the spinal cord 

There is an additional risk that brain herniation may occur if the person being tested has a mass in their brain. This is very serious and can result in brain damage or death. Because of this, a spinal tap is not done if an exam or test shows signs of a brain mass.

The information contained in this article is meant for educational purposes only and should not replace advice from your healthcare provider.