LARGE INFERIOR RIGHT HEPATIC VEIN - CLINICAL IMPLICATIONS

The right middle and inferior hepatic vv. are very frequent, indeed co nstant, but usually of small caliber. The presence of an extra-wide ri ght inferior hepatic v., usually solitary, produces a variation in the venous drainage of the right lobe of the liver. The right inferior he patic vv. reaching or exceeding a caliber of 0.5 cm were investigated in 125 anatomic liver specimens: 70 injection-corrosion specimens, 32 formolised livers and frontal or frontal-oblique sections of the trunk made in 23 cadavers. The incidence of such vv. was estimated at 9% in the injection-corrosion specimens, 13% in the sections and 16% in the formolised livers. The incidence of these vv. in the literature varie s from 10% to 24% according to the method used to demonstrate them. Us ually, there is a balance between the right superior and inferior hepa tic vv. Rarely, the right inferior hepatic v. predominates compared wi th the right superior hepatic v. The position of an extra-wide right i nferior hepatic v. is constant, close to the visceral aspect of the li ver. Its appropriate territory is segment VI, but it may encroach some what on adjacent segments. Clinically, the existence of an extra-wide right inferior hepatic v. as detected by MRI and, especially, located by intraoperative ultrasonography, allows performance of a subtotal he patectomy leaving only segment VI. In certain pathologic conditions, t hanks to the development of anastomoses between the hepatic vv., an ex tra-wide right inferior hepatic v. may contribute to a compensatory ci rculation towards the right atrium.