main vein

So his doctors had chosen to put a filter in the main vein that brought blood from his legs back to his heart — a vessel called the inferior vena cava — to catch any clots that formed and broke free.

“We’re the main vein of the country,” Joe Weiss, the general manager of the Mud Island Marina in Memphis, said as he sat on a dock that looked like it had been plopped down in a muddy parking lot.

While Roman art featured plenty of little boys, often in cherub form, few were draining their main vein.

I’m going to miss writing a story when, slogging through hours of rewrites, I’ve finally hit the main vein.

Though the main vein of McCarthyism petered out in the late '50s, the Lavender Scare lived on in other branches of the government, notably through the military's Don't Ask, Don't Tell policy.