A plexus of veins surrounds the rectum and drains chiefly into the superior rectal vein, which is a tributary to the inferior mesenteric vein. The paired middle and inferior rectal veins drain into the internal iliac veins. Return to Question 7 7. Distinguish between internal and external hemorrhoids. Hemorrhoids are varicose dilations of veins in the rectal submucosal venous plexus.
Internal hemorrhoids lie above the pectinate line and drain into the superior rectal vein.
External hemorrhoids are below the pectinate line and drain into the inferior rectal veins. Return to Question 8 8. To the body of the pubis. Return to Question 10 10. Return to Question 11 11.