I used to teach a History of Medicine course as part of the UK School Council History Project. Within it I would cover the work of Leonardo Da Vinci in his development of anatomically correct images of animals and humans, which he would use to ensure that the texture and underlying musculature of his paintings and sculptures were as lifelike as possible.
It was therefore very gratifying to find these marvellous drawings, which are now available as an app from iTunes:
iTunes.com link: https://itunes.apple.com/ca/app/leonardo-da-vinci-anatomy/id520564038
iTunes UK link: