No part of the body has been found to significantly correlate with penis size other than the size of your penis.
DNA called, it says "Hello, I am in every part of the body, and dictate almost every physical aspect of you. What were you just saying?"
Of course, you HAD to use the word "Correlate," which can be interpreted differently simultaneously, for there is a mutual connection/relationship yet little to suggest any dependencies or resulting affect from a change like from an (un)definable past/present influence, either ex-/internal.
Perhaps we are just not being 'creative' enough (wink-wink), for in general it is not uncommon for some parts of the body to correlate with other parts of the body where size (to some degree and parameter) bearing in mind that there are always exceptions to every rule especially to generalizations without discounting the validity of the rule/generalization.
Captcha: no time to explain
How does it do that?