A fascial canal for the great saphenous vein: gross and microanatomical observations.

The course of the great saphenous vein in a fascial canal derived from the deep fascia of the lower extremity is described. The fascial canal is absent in 15% of the cases. In 85% of the cases, the sheath surrounding the great saphenous vein is continuous from the thigh to the leg and supports the vein from the hydrostatic pressure of the blood, being absent only in the uppermost and the lowermost quarters of the vein in the thigh and the leg, respectively. Thus, up to one quarter of the vein is ensheathed in 30%, up to one half in 45% and up to three quarters in 10% of the cases studied. The absence of this fascial envelope of the vein, in whole or in part, may be involved in the pathogenesis or the complications of the varicosities of the great saphenous vein along with the well-known aggravating factors.