Even an anatomical master like Michelangelo had some trouble with the female form. Consider his tomb sculptures for the New Sacristy of San Lorenzo. There, the female personifications of Night and Dawn have distinctly male-looking chiseled torsos beneath wide-set breasts that are as bulbous and affixed looking as any inept plastic surgery. The lack of access to female models explains the odd female anatomy of many Renaissance and Baroque nudes. (No one can explain the plethora of strange babies.)
