In which vein of the upper thigh is deep‑vein thrombosis most common?

DVT Location in the Upper Thigh

In the upper thigh, deep vein thrombosis most commonly occurs in the femoral vein, with 70-90% of identifiable thromboemboli arising from the femoral and iliac veins when the source can be determined. 1

Anatomical Distribution in the Upper Thigh

The upper thigh contains several deep veins where DVT can occur:

• Femoral vein (most common): Among patients where the thromboembolism source is identified, the femoral vein is the most frequently affected site in the upper thigh region 1
• Common femoral vein (CFV): Approximately 27% of DVT patients have iliofemoral involvement, with the CFV serving as a critical junction point 2
• Deep femoral vein (profunda femoris vein): Present in 23.1% of proximal DVT cases, though this typically occurs in conjunction with other venous involvement 3

Clinical Significance by Location

The femoral vein location carries substantial clinical importance because:

• DVT involving the thigh increases pulmonary embolism risk to 67%, compared to only 46% when confined to the calf 1
• When pelvic veins are also involved, the PE risk escalates further to 77% 1
• Proximal DVT (including femoral vein) is strongly associated with 50-60% PE occurrence in untreated cases, with mortality rates of 25-30% 4

Common Femoral Vein Patterns

When DVT extends into the common femoral vein specifically:

• If the CFV shows only partial (non-occlusive) thrombus with patent deep femoral vein inflow, the DVT is more likely confined below the inguinal ligament 5
• If the CFV demonstrates occlusive thrombus, there is 77% likelihood of concurrent iliac vein involvement 5
• When CFV DVT is present, 49.1% of cases also involve the ipsilateral deep femoral vein 3

Deep Femoral Vein Involvement

The profunda femoris vein (deep femoral vein) warrants specific attention:

• When involved, 91.7% of cases also have ipsilateral CFV thrombosis 3
• PFV DVT patients demonstrate higher thrombus burden with more frequent concurrent external iliac vein (21.7%) and femoropopliteal vein (65%) involvement 3
• These patients are more likely to have underlying hypercoagulable disorders (26.7% vs 14.5%) and history of immobility (58.3% vs 42%) 3

Diagnostic Implications

Complete evaluation of the upper thigh requires:

• Ultrasound protocols must routinely examine the deep femoral vein, as it serves as a marker for more extensive thrombotic disease 3
• In patients with femoral DVT on ultrasound, consider axial imaging of the iliocaval system, as 67% may have additional central pathology warranting intervention 6
• The majority (80%) of patients with acute iliofemoral DVT have underlying anatomic abnormalities identifiable on imaging 7