Oh, my aching head!

I recently wrote about penetrating trauma. Today's blog is the first in a series about the much more common, and subtle, blunt trauma. This refers to any trauma from an object striking the body (baseball bat?) or the body inpacting something solid (the ground at the end of a fall). The laws of physics apply to this type of trauma. Energy equals weight times velocity to the second power. Inertia is the tendency of moving objects to continue to move unless acted on by an outside force. This is abundantly evident to those unfortunate and foolish individuals who don't use seatbelts. When the car stops suddenly, the occupants' inertia often throws them out of the vehicle. We in the ER refer to people who ride motorcycles and those who choose to drive in cars without seatbelts as OD (organ donors).



Let's start at the top. The brain is encased in a very solid structure, the skull. The brain is covered by the meninges. They are made up of two thin and one thick membrane that wrap around the brain. There is a small amount of fluid (cerebral spinal fluid, CSF) surrounding the brain and CSF filled cavities(ventricles) within the brain. The arteries and veins that lie under and around the brain are prone to tearing due to direct trauma or deceleration. When bleeding occurs in the rigid skull, the brain will become compressed causing damage to the neurons and herniation of the brain downwards. The foramen magnum is the hole at the base of the skull that is the passage from the brain into the spinal cord. When the pressure from accumulating blood or swelling of the brain tissue builds up, and the brain is forced (herniates) through the foramen magnum, only emergency neurosurgery can save the victim's life.



Deceleration injuries occur whenever the head is moving, and stops abruptly. The head snapping back and forth during a car accident, or when a child is shaken, are prime examples of this type of injury. The impact of the head against a solid object as in a fall or inside a vehicle during a car accident, also causes a sudden decelaration. The outside of the head stops but the brain continues to move until it strikes the inner aspect ot the rigid skull, There are bony ridges in the skull that multiple the damage to the brain. The striking of the brain against the skull and the rebounding and secondary strike on the opposite side is refered to a coup-contracoup injury.

The elderly are particularly prone to intracranial bleeding from even minor blows or deceleration events. The brain atrophies (shrinks) as we age. The space in the cranial vault allows the brain to move more easily. Coup-contracoup injuries and tearing of stretched veins are much more common in older patients. The extra space also allows for bleeding or swelling to not be as apparent, before increased pressure causes damage to the brain or herniation.


Direct impact of the head from objects (sticks and stones...) can fracture or crush the skull. Vessels between the skull and brain can be torn by the fragments of the bony skull. The fracture may force the bones to directly injure the brain. The bones of the face may absorb some of the energy from a direct blow. Fractures involving the facial bones may lead to leaking of CSF and are a potential source of contamination of the brain by bacteria.



A concussion is an injury to the brain that causes dysfunction of the mental processes. A loss of consciousness may or may not occur. Alterations in memory, thought formation, balance or wakefulness appear to some extent. Concussions are graded from first to third degree from minor to severe. The neurological exam is crucial to look for actual structural injury to the brain. An absence of focal (weakness, speech disturbance, visual loss) injury, with a CT that is negative for bleeding, is reassuring that no serious injury to the brain has occured. An MRI may show more subtle injuries to the brain tissue than a CT. Neuropsychological tests are being administered to atheletes to establish a baseline that can be used to assess the impact of a subsequent concussion.



Much has been written and reported in the press, on TV, and the internet about concussions. Subtle abnormalities in tests of coordination and reasoning can be shown even with minor concussions. The key is for recognition of the concussion and the prevention of any further injury to the brain. The higher the degree of concussion, the more time is needed for a complete recovery. Second or third concussions may lead to early onset dementia. Dementia pugilistica (witness Muhammid Ali) is well recognized in boxers but is now known to occur in football players and other athletes who sustain repetitive head injuries.


Appropriate protective head gear and common sense are your best defense. Any loss of consciousness, confusion, memory loss or persistent vomiting after a head injury requires medical evaluation. Let's keep our "wits" about us.