On top of that, not every one has the same tissues in the same places, or the same tissues at all. Most famous is the palmaris longus muscle in the arm. https:

On top of that, not every one has the same tissues in the same places, or the same tissues at all. Most famous is the palmaris longus muscle in the arm. https://en.wikipedia.org/wiki/Palmaris_longus_muscle https://en.wikipedia.org/wiki/Palmaris_longus_muscle ~14% of humans lack this muscle. Other deviations range from colorblindness all the way to lack of a cerebellum entirely. Humans are quite variable, even when healthy.