I already discussed the possibility that two of the drawings on fol. 77v of the Voynich Manuscript represent the anatomy of the intestines and the appendix (click here). Curiously Leonardo da Vinci also chose to zoom-in the appendix and draw it separately on the same page as the intestines.
This particular drawing of Leonardo is dated 1492, so the picture would have been available in 1494 when da Vinci accompanied Ludovico Sforza to Pavia to meet the French King Charles VIII during his Italian War. Leonardo also met on the same trip the anatomist della Torre (click here ) and thus inspired the royal physician/astrologer/prophet/poet Jean Michel to make similar composition in his book that was captured later at the battle of Fornovo and smeared publicly because of all the naked women in it. OK, the part about Jean Michel is all speculation, of course.