Bump on a Bone - pls help me!?

why is it that when you bump a bone against something hard, a bump grows on that spot?? i dont know what the term is in english, sorry, but i'll describe it as best as i can:
for eg, when you bump your head, a bump grows. now does that also happen on other bones (apart from the head). cos yesterday i fell from my bike and hit my tibia on a sidewalk. when i arrived home i realised i had a bump on the tibia bulging outwards, and i felt pain on the surrounding area. also, the area turned sightly yellow (not much).
when i arrived home i put some ice on my leg and rested it for maybe half an hour.today the bump is still there and the surrounding area still a little painful if i touch it. but the yellow colour is gone.should i worry or this is nothing??i never had broken bones before and dont know anyone who had, so i cant check if i broke something.ps note that i found no difficulty riding the bike back home (about 5 mins ride) and walking and running.
Answer:
i have broken both bones and dislocated it all at the same time
a skating inccedent
and the yellow is the bruise developing
don't worry about it
get worried if it still hurt a week from now :)
yes and i also smashed my shin once jumping onto a football table (fuzzball) if u like
and it swelled up like 10 fold and bled alot but i had not problem skating home
i belive it was the adrenaline(u americans call it something else i think)
so it doenst hit home for a good 5 10 mins
dont worry Be happy :)Mr IP

---

I found an article about your question on the answer search engine.
The link is in my source.

---

When you hit that spot, blood vessels burst, causing swelling around that spot.

---

If you hit a bone hard enough, it will react in the same way that it would react if you had broken it; that is, it will start laying down new bone over the area.
Most of the time, when people break bones they have an instictive feeling that the bone is broken, Trust me, if you had broken the bone, you would know it.

---