What is the first step when performing a lumbar puncture (LP)?

Updated: Aug 02, 2018
  • Author: Gil Z Shlamovitz, MD, FACEP; Chief Editor: Helmi L Lutsep, MD  more...
  • Print
Answer

Wearing nonsterile gloves, locate the L3-L4 interspace by palpating the right and left posterior superior iliac crests and moving the fingers medially toward the spine (see the image below). Palpate that interspace (L3-L4), the interspace above (L2-L3), and the interspace below (L4-L5) to find the widest space. Mark the entry site with a thumbnail or a marker.

L3-L4 interspace palpation. Image courtesy of Gil L3-L4 interspace palpation. Image courtesy of Gil Z Shlamovitz, MD.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!