Femoral Vein

Introduction

Introduction to the Femoral Vein

The femoral vein is the main deep venous channel of the lower limb. It begins at the adductor hiatus as the continuation of the popliteal vein and ascends through the adductor canal and femoral triangle to become the external iliac vein deep to the inguinal ligament. It accompanies the femoral artery throughout its course, but its relationship to the artery changes from posterolateral to medial. The femoral vein receives the great saphenous vein and the profunda femoris vein, and is a crucial site for central venous access, venipuncture, and the diagnosis of deep vein thrombosis (DVT). Its superficial position in the femoral triangle makes it accessible but also vulnerable to injury.

Study

1. Origin and Termination

The femoral vein begins at the adductor hiatus, a tendinous opening in the adductor magnus muscle, as the direct continuation of the popliteal vein. It terminates by passing deep to the inguinal ligament to become the external iliac vein. The junction is at the level of the mid‑inguinal point.

2. Course and Relations

The femoral vein ascends in the adductor canal (subsartorial canal) where it lies posterior and slightly lateral to the femoral artery. As it enters the femoral triangle, the vein comes to lie medial to the artery within the femoral sheath. In the femoral triangle, the vein is enclosed in the middle compartment of the femoral sheath, between the femoral artery (lateral) and the femoral canal (medial). The femoral nerve lies lateral to the sheath. The vein is crossed superficially by the great saphenous vein, which joins it at the saphenofemoral junction, and by the superficial external pudendal artery. The profunda femoris vein drains into the femoral vein about 4 cm below the inguinal ligament.

3. Tributaries

The femoral vein receives several tributaries: (1) The great saphenous vein, which pierces the cribriform fascia to join the femoral vein at the saphenous opening; (2) The profunda femoris vein, which drains the deep thigh muscles and joins the femoral vein posterolaterally; (3) The lateral and medial circumflex femoral veins, which accompany their arteries and drain into the profunda femoris or directly into the femoral vein; (4) Small muscular and cutaneous veins.

4. Valves

The femoral vein contains several bicuspid valves that prevent retrograde flow. A valve is consistently found just distal to the junction with the profunda femoris vein, and another valve is present near the inguinal ligament. These valves are important in maintaining venous return and can become incompetent, leading to varicose veins.

5. Clinical Relevance

The femoral vein is a common site for central venous catheterisation for haemodialysis, parenteral nutrition, and emergency venous access. It can be punctured just medial to the femoral artery in the femoral triangle. Deep vein thrombosis (DVT) commonly involves the femoral vein, presenting with a swollen, tender thigh. Iliofemoral DVT is a severe form that may cause phlegmasia alba dolens or phlegmasia cerulea dolens. The femoral vein can be injured in penetrating trauma, femoral fractures, and during groin surgery. During varicose vein surgery, the saphenofemoral junction is ligated, and the surgeon must identify the femoral vein to avoid injury. Compression ultrasound of the femoral vein is used to diagnose DVT.

Summary

Summary of the Femoral Vein

The femoral vein is the main deep vein of the lower limb, ascending from the adductor hiatus to the external iliac vein. It lies initially posterolateral, then medial to the femoral artery within the femoral sheath. Key tributaries include the great saphenous vein and the profunda femoris vein. The vein is clinically important for central venous access, as a site of DVT, and for surgical exposure during varicose vein and hernia operations.