[Does the inferior vena cava have 2 surfaces and 2 borders also?].

The vena cava that has a preferential flattening axis, has also 2 wall sides and 2 borders. The back wall fits closely round on the back vertebral plane and the main colaterals terminate on the borders of the vein. TM echography perfectly analyses the movements of the walls of the vein, as well as the respiratory and auricular movements. In a lying patient, echo-doppler colour shows the expiratory acceleration of the vena cava flow in subrenal area associated with an inspiratory slowing down (as well as for the femoral veins) and the inspiratory acceleration of the flow in suprarenal area associated with an expiratory slowing down. In a standing patient, the vena is cylindrical. When he/she walks on a treadmill, the diameter of the cava seems to be constant, i.e. quasi identical to the aorta's, as fluxes vary in the aorta according to the ventricular contractions and in the LVC according to the patient's gait.