Linear skull fracture: A common injury, especially in children. A linear skull fractures is a simple break in the skull that follows a relatively straight line. It can occur after seemingly minor head injuries (falls, blows such as being struck by a rock, stick, or other object; or from motor vehicle accidents). A linear skull fracture is not a serious injury unless there is an additional injury to the brain itself.
Depressed skull fractures: These are common after forceful impact by blunt objects—most commonly, hammers, rocks, or other heavy but fairly small objects. These injuries cause "dents" in the skull bone. If the depth of a depressed fracture is at least equal to the thickness of the surrounding skull bone (about 1/4-1/2 inch), surgery is often required to elevate the bony pieces and to inspect the brain for evidence of injury. Minimally depressed fractures are less than the thickness of the bone. Other fractures are not depressed at all. They usually do not require surgical treatment unless other injuries are noted.
Basilar skull fracture: A fracture of the bones that form the base (floor) of the skull and results from severe blunt head trauma of significant force. A basilar skull fracture commonly connects to the sinus cavities. This connection may allow fluid or air entry into the inside of the skull and may cause infection. Surgery is usually not necessary unless other injuries are also involved.
Intracranial (inside the skull) hemorrhage (bleeding)
Subdural hematoma: Bleeding between the brain tissue and the dura mater (a tough fibrous layer of tissue between the brain and skull) is called a subdural hematoma. The stretching and tearing of "bridging veins" between the brain and dura mater causes this type of bleeding. A subdural hematoma may be acute, developing suddenly after the injury, or chronic, slowly accumulating after injury. Chronic subdural hematoma is more common in the elderly whose bridging veins are often brittle and stretched and can more easily begin to slowly bleed after minor injuries. They are potentially serious and often require surgery.
Epidural hematoma: Bleeding between the dura mater and the skull bone is an epidural hematoma. These occur when arteries are cut. Injury in the temple area is a common cause. Epidural hematoma is potentially serious and often requires surgery. Intraparenchymal hemorrhage/cerebral contusion: These terms describe bleeding into the brain tissue itself.
A contusion is like a bruise to the brain tissue and usually requires no special intervention, much like a concussion. Most doctors admit people with cerebral (brain) contusion into the hospital for observation for rare complications such as brain swelling. An intraparenchymal hemorrhage is a pool of blood within the brain tissue. Minor bleeding may stop without any treatment and cause no serious problems. More serious or large bleeds usually require surgery.
Closed head injuries: This broad term describes any injury to the brain or structures within the skull that are not caused by a penetrating injury (such as a gunshot wound or stab wound). They range from very minor to potentially fatal injuries.