The most common is blunt force trauma. If you were involved in a car accident or any other type of sudden hit, your brain could suffer as a result. In addition to automobile accidents, injuries can occur from falling, fighting, or anything else that can cause a hit to the head. Sometimes it can be an affect from another injury (e.g., concussion caused from being hit in another part of the body). There are many signs that you may have a brain injury, but some of the most common include loss of consciousness, headaches, vomiting, and sleep disorders (too much or too little).