– Some institutions offer DVD rentals through interlibrary loan, or you might find used copies at reduced prices (e.g., eBay, Amazon marketplace).
While a free download of the entire commercial product is generally not legal or safe, there are legitimate ways to access the content for free or at a low cost. acland dvd atlas of human anatomy free download free
If you tell me your country or whether you have university/library access, I can suggest specific legal sources or libraries to check. – Some institutions offer DVD rentals through interlibrary