I think they come from different ends of the cow!
I made this recipe with cross cut shank last week. Best $2.99lb beef I’ve ever eaten....
http://www.bbcgoodfood.com/recipes/1660659/rich-braised-beef-with-melting-onions
Now my curiosity is stirred up. I’ll have to put it on my grocery list,along with some turkey oven bags!