For lumbar puncture, the needle is typically inserted at the L4–L5 or L3–L4 interspace. The surface landmark used to identify the L4 vertebral level is:

• A Inferior angle of the scapula
• B Iliac crest (Tuffier's line) ✓
• C Posterior superior iliac spine
• D Xiphisternal junction

Explanation

A horizontal line connecting the highest points of both iliac crests (Jacoby's or Tuffier's line) corresponds to the level of the L4 vertebral body or L4–L5 interspace. This is the standard surface landmark for safe lumbar puncture, as the spinal cord ends at L1–L2 (conus medullaris) in adults; inserting below L3 ensures the needle enters the subarachnoid space without cord injury. The posterior superior iliac spine approximates S2.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.