 Holodets blues         Holodets is a typical Eastern Europe recipe. It is is basically a meat aspic, the gelatin being obtained from long boiling the bones and melting the connective tissue-collagen.  I tried to do holodets using cow bones (no pig feet, that one is easier).    My problem is that I can't figure out from the recipes which bone is used. It's mentioned as "hoof", "knee", "leg bone", etc. But there is no photograph and bone names vary from place to place.    I prepared the dish but the collagen content of the bones I used was not enough, so I ended up adding agar-agar, which I know is not needed if the bones are "the correct ones".    Can anyone to help me to identify the bones? A photograph should be the optimal answer!    NB> Please feel free to correct my English 
The Russian lady that taught me how to make Kholodets used a chunk of femur.  She would simmer for at least 5 hours the bone with a good bit of meat still on it. As the broth cooled she would remove the meat from the bone, chop it and put it back into the pot along with a sizeable amount of sliced garlic.  After chilling in the fridge (usually overnight) she would remove the fat that accumulated on top and serve with a very khrenoviy mustard.  I'm sure that a joint would have worked just as well- it just wouldn't have as much usable meat.  I'm sorry I don't have pictures. 