Take the discussion down a joint or three:

Hallux valgus is commonly known as a bunion. The two affected big-toe joints would bang into each other if you walked without shoes.

Now move the image up to your knees. That's knock-kneed, for the analogous reason. The officiousofficial term is genu valgus. That's "genu" as genuflect (= "knee bend").

The bow-legged, concave-in, knee is genu varus.

There is a twisted consistency in that medical terminology.