Beef shanks are cut from the beef hind leg. They have a large bone that is usually removed before cooking, but can be left on for flavor and presentation purposes (e.g., Beef Shanks Braised in Red Wine).
Beef shanks are cut from either the hind legs or forelegs of the steer. Due to its size, the beef shank cut from the hind legs tend to be meatier than if cut from the foreleg. Beef shanks are great for slow cooking and because of the meat flavor and bone marrow, they provide great flavor for soup!