I'm a bit surprised that two mods endorse closing...
...citing "Lack of context". After failing to find the exact text in Google Books, I searched the whole Internet, and found just one instance - on someone's Facebook page.
BUT when I (reluctantly - I don't like FB) followed the link from Google, I couldn't actually find the text myself (buried somewhere in a Read more... post, I guess). I've added a screenshot giving the limited amount of context from the Google search "snippet view", but imho the intended meaning was obvious without even that.
So far as I'm concerned, it's a typically Anglophone "whimsical coinage" building on established idioms like My little finger knows more than your head (you're really dumb). I don't know if any other languages make such superficially nonsensical assertions involving body parts - but even if they all did, I'm not convinced that would justify closing the question.