Viet Hapa Pho recipe question: What are "beef bones" (i.e., short ribs) and oxtail?

I buy "Beef Knuckles" when I need "beef bones". They are available at my local Asian grocer. Shorts may have too much fat. Knuckles are good because they are mostly bone and have tons of connective tissue (i.e. collagen -> mouthfeel).

Hey, the bones and oxtails are used to make a richer and more flavorful broth. Beef bones are pretty self explanatory and the oxtail are as well - the cows tail. There's not much meat on it and it has a lot of gelatinous tissue that breaks down into soft yumminess when you braise it for a long period of time. You can visit Fairway Market and ask specifically for the short ribs an oxtails from the butcher shop. Let them know you're making Pho and they will provide you with everything you need. Good luck!