Is it possible to break the tip of my big toe bone? three days ago i sat on a chair without balance and caught it under my big toe. it is bruised under where the nail starts to grow. i can barely move the joint and it hurts to walk on it. my whole toe is

Well, : Well, there are other things that could be going on besides a fracture, given your (excellent) description and information supplied. You could have a collection of blood either under the nail or deeper inside above or near the bone (hematoma), that can cause pain due to the pressure build-up of the blood, and this can press against nerves and even cut off circulation to the end of your toe. There could also be some damage to the nerves of the toe itself from the injury which could also explain your pain. So my short answer is go to a doctor, have it looked at and x-rayed, there might be nothing to do, but you'll never know unless you go. Feel better.

Fracture: Yes, sounds like fracture. Buddy tape it and check with orthopedic foot surgeon if ecchymotic nail. Hard sole shoe.

Big toe: Yes - a fracture is possible . As stated , there could be several other things going on as well . See your podiatrist for x rays and an exam and you will know as well as get the treatment you need. As said , the accumulation of blood under the nail can be an emergency as it can prevent needed blood form getting to the area