Femoral Vein

Anatomy

The femoral vein is the primary deep vein of the thigh. It begins at the adductor hiatus (Hunter's canal) as the proximal continuation of the popliteal vein, and ends at the inferior margin of the inguinal ligament, where it becomes the external iliac vein.

It is contained within the femoral triangle, whose boundaries are:

Superiorly - inguinal ligament
Laterally - sartorius muscle
Medially - adductor longus muscle

(Mnemonic for the triangle: SAIL - Sartorius, Adductor longus, Inguinal Ligament)

Relations - NAVEL Mnemonic

From lateral to medial within the femoral sheath:

Letter	Structure
N	Nerve (femoral nerve)
A	Artery (femoral artery)
V	Vein (femoral vein)
E	Empty space
L	Lymphatics

Note: As the artery and vein course distally, their relationship can rotate so the artery may lie on top of the vein - this is why ultrasound guidance helps avoid accidental arterial puncture.

Tributaries

The deep femoral vein (profunda femoris) drains into it posteriorly, about 8 cm distal to the inguinal ligament. Proximal to this junction, it is called the common femoral vein.

Clinical Importance

1. Central venous access: The femoral vein is the most accessible central access site during critical illness - especially during cardiac arrest or trauma - because it does not require stopping CPR and avoids risks of pneumothorax.

Cannulated 1-2 cm below the inguinal ligament, just medial to the femoral artery pulse
In pulseless arrest, use the "V" technique: thumb on pubic tubercle, index finger on ASIS - the vein lies at the interdigital space

2. Deep Vein Thrombosis (DVT): The femoral vein is a common site for DVT, which can embolize to cause pulmonary embolism (PE). The superficial femoral vein (despite its name) is a deep vein and DVT here carries the same embolic risk.

3. Femoral venous duplex ultrasound is the standard method for DVT diagnosis.

Sources: Roberts and Hedges' Clinical Procedures in Emergency Medicine; Tintinalli's Emergency Medicine: A Comprehensive Study Guide

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