Ultrasonography of the femoral vessels in the groin: implications for vascular access.

The femoral artery and vein are commonly used for access to the circulation. Accidental puncture of one vessel whilst attempting to cannulate the other is a common complication. Identification of relevant surface anatomical landmarks and ultrasonography of both groins was performed on 50 consecutive adult patients admitted to the intensive care unit. In most patients there was overlap of the artery over the vein far closer to the inguinal ligament than conventional anatomical texts would indicate. The frequency and degree of overlap increased as the vessels descended distally towards the knee. Surface anatomical landmarks were not useful in predicting the underlying anatomy. The side-by-side relationship of artery and vein is commonest close to the inguinal ligament. Therefore, to avoid damage to the neighbouring vessel, percutaneous access should be undertaken just below the inguinal ligament.