So I was at a basketball game, and sometime mid-way through it, I got elbowed in the head. At the end of the game, I found that I got a small cut that was slightly bleeding and, at that point, the blood had sorta dried. So how is it that I got a cut (it resembles a cut from a knife; straight and no width) on my head from being elbowed? I felt a little bit of pain that felt like it was coming from the bone, as I've felt that pain before and could recognize it, right after being elbowed. After the game, I didn't feel any pain until I took a shower. Then there was a really sharp pain. So, yeah, how did I get a cut from being elbowed in the head?
There are a few different types of injury to the skin. You can have a contusion (Bruise), abrasion (scrape), puncture, laceration or incision. The injury that you suffered is a laceration, as opposed to an incision. The main difference between the two is the cleanliness of the edges, lacerations are more jagged, incisions are clean slices.
There's a few different reasons that this could occur, but basically it's because the skin was suddenly stretched or compressed beyond it's ability to hold shape, and a tear results. You can see a few different laceration causes at this page. This can be fairly common in the head, as the skin is very close to the bone in most areas of the face and head.
Depending on the depth, location and severity, it can be taken care of from anything starting with a bandaid, up to wound glue or sutures.