If you look at a lot of cartoon characters you can see how they stylize the skeletal structure of the legs so animal characters walk like a person.
This is what I did with my own Larry Liger character. I put the "feet" flat on the ground. The knees then become regular knees and the feet are just big floppy funny feet.
BTW Aside from looking at the image, I primarily discovered the similarities by feeling with my fingers how my cat's bones are oriented alongside his body. What I always assumed where parts of the chest sticking out on both sides, are actually upper front leg bones, the humerus (or: humerous in UK English). This means the ribcage of a cat is much narrower than you'd expect. It perhaps also explains why my cat can balance on the back of a chair with ease.
Cats seem to have much in common with horses, even some of their gaits seem to coincide, I've read somewhere. And speed too, because my cat can sprint at 50 kph (30 mph) easily, for 200 m, with his leash dangling behind him and his owner in awe that such a small animal can run 3 times as fast as him. Of course, being a Bengal cat he is much more muscular than any other cat breed.
As you're a native UK English speaker, I believe you. I saw the spelling on an UK English medical website, which, in hindsight, obviously has a typo.
Nevertheless, Googlefight states that there are 600,000 mentions of "humerous" against 926,000 mentions of the correct spelling "humerus". I guess "humerous" is either "humorous" or "humerus".
It seems the Internet isn't a good reference for knowledge, and certainly not for correct spelling.
Well, either I'm talking out of my arse again (always a possibility!) or 600,000 people don't know their Latin...Personally, I don't know any Latin word that ends in "ous" -- and I did Latin at school.
You can't have everything. Where would you put it?