Head injuries can be among the most dangerous injuries. They can cause brain damage or even death. Common reasons for head injuries are sports such as football, cycling, basketball, baseball, soccer, and more. Signs of a head injury include dizziness, nausea, memory loss, feeling foggy, changed vision, change in the size of pupils, and many more. Follow the links below to find WebMD's comprehensive coverage about how head injuries are caused, symptoms of a head injury, treatments, prevention, and more.