Page 52 - Libro 2

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PART 1 — INTRODUCTION TO THE VASCULAR SYSTEM
Superficial veins
Deep veins
Perforating veins
Rest
Contraction Relaxation
Muscle
Figure 3-10 Patterns of normal venous flow at rest and with calf contraction.
there may be a degree of residual venous obstruction (Fig. 3-12). Because of the obstruction, the super- ficial veins may function as collaterals, and blood may flow out from the deep to the superficial veins even at rest. Venous flow patterns are completely
disrupted in these patients. The flow through the perforators can be bidirectional, thus increasing pressure within the superficial system. More blood is forced distally because of the incompetent valves in both the deep and superficial systems resulting in
Superficial veins
Perforating veins
Deep veins
Incompetent superficial valves
Rest
Contraction
Relaxation
Muscle
Figure 3-11 Patterns of venous flow with primary varicose veins.