+Elena

☺ Though I don't know where else the legs can be bent...

At the ankles and at the ass

Again, if you search "согните ноги в" in yandex, for example, the results show only "коленях". As to ankles - we say "сгибать голеностопный сустав"

Или "сгибать стопу" (не ноги)
As to the ass, we usually say "сгибать тазобедренный сустав"

I was kind of joking, but that's interesting to know

😁