Musicians and artists are not unusual in medicine and those talents are respected and valued. I personally know several surgeons who are painters and sculptors. Two of them have sold many pieces.
I agree with what Lizzie said above: Someone reading your application might be intrigued enough to ask you in for an interview when they might not otherwise have invited you. If your application is otherwise competitive, it could garner some extra interviews.
Definitely talk about the art, and definitely mention the lab manual. The lab manual will help validate the art, in that it will demonstrate that you talent is real. It will give you an opportunity to show samples of your work, if asked. I suggest that you bring along a copy of the lab manual to interviews, either as a hard copy or at least on a thumb drive, in the event that you are asked about it ( but ONLY if asked). You could also include some of your other work on the drive, so that you could casually show what else you have done if asked. Of course, the work you did for the lab manual will also show how your art is relevant to medical school. I know that the typical advice for students is not to turn an interview into a "show and tell", but I would recommend being prepared to do so in this case. At the very least, you could put copies of your work on your phone.
Just be sure that you know who Frank Netter was, and make sure that you look at his books before your interviews. ( I use the Netter atlas as my primary anatomy book for surgery. ) Also, to flesh-out Lizzie's excellent suggestion above, note that the full name of Quinnipiac med school is the Frank H. Netter School of Medicine at Quinnipiac.
