What exactly are hemorrhoids?

Swollen anal vein: There are veins in the anus called the hemorrhoidal veins. When they swell they can develop a clot. The clot causes pain and makes it hard for the vein to shrink back to its baseline size. The swollen clotted anal veins are hemorrhoids. They usually occur with straining such as constipation, heavy lifting, breath holding and child birth.

Hemorrhoids: Hemorrhoids are nothing more than dilated blood vessels . They are easily shrunk down but if they become thrombosed (a clot inside), they need to be surgically cut open.