Lumbar puncture; drawing shows a patient lying in a curled position on a table and a spinal needle (a long, thin needle) being inserted into the lower back. Inset shows a close-up of the spinal needle inserted into the cerebrospinal fluid (CSF) in the lower part of the spinal column.

Lumbar puncture. A patient lies in a curled position on a table. After a small area on the lower back is numbed, a spinal needle (a long, thin needle) is inserted into the lower part of the spinal column to remove cerebrospinal fluid (CSF, shown in blue). The fluid may be sent to a laboratory for testing.