For a femoral nerve block, the needle is inserted just lateral to the femoral artery at the level of the inguinal ligament. Using the mnemonic NAVL (medial to lateral), the correct order of structures at the femoral triangle at this level is:

• A Vein – Artery – Nerve – Lymphatics (lateral to medial: V-A-N-L)
• B Artery – Vein – Nerve – Lymphatics (lateral to medial: A-V-N-L)
• C Nerve – Artery – Vein – Lymphatics (lateral to medial: N-A-V-L) ✓
• D Nerve – Vein – Artery – Lymphatics (lateral to medial: N-V-A-L)

Explanation

Under the inguinal ligament from lateral to medial the order is: Nerve (femoral) – Artery (femoral) – Vein (femoral) – Lymphatics (lacuna vasorum medially). This is remembered as NAVL or the acronym 'NAVY' (nerve-artery-vein). The femoral nerve is enclosed in a separate fascial compartment (lateral to the vessels) and is NOT within the femoral sheath (which contains artery, vein, and the empty canal medially). Therefore, for femoral nerve block the needle goes lateral to the femoral artery pulse. For femoral vascular access the needle targets the artery directly.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.