This article is a continuation of a two-part article on traumatic brain injury. Part 1 covered severe traumatic brain injury while part 2 addresses
During trauma, illustrated above, the brain impacts against the inside of the skull. Shearing injuries often occur because the gray and white matter are of different densities; therefore, the axons tear at the junction of the white and gray matter. The injuries can consist of torn or twisted axons, or the axons can pull away from their synapse.
Axonal injury can also occur without the head striking an object. This often occurs in collisions. During a sudden deceleration injury, the brain impacts the inside of the skull in a coup - contrecoup fashion, which means that the brain first impacts the area of the skull receiving the trauma and then impacts the area of the skull directly opposite of the trauma, as seen in the animation below. As a result, shock waves of the forces travel through the brain.
The loss of the sense of smell is an indicator of traumatic brain injury. The image below depicts the normal olfactory anatomy with the olfactory nerves extending through the cribiform plate and innervating the nasal passages. During trauma to the head, the forces can be great enough to sever the relatively large olfactory
nerves, which affects the sense of smell. Forces sufficient to injure the olfactory nerves are certainly sufficient to result in diffuse axonal injuries throughout the brain whether evident on imaging studies or not.
1) Rely on changes of behavior and cognitive function as reported by family members, coworkers and friends. Casual examinations by a physician may not result in a diagnosis.
2) The absence of physical brain injuries on traditional MRI or CT DOES NOT RULE OUT brain injuries.
3) Correlation of traumatic forces with injury to the specific areas of the brain that control those functions is very important when proving a “mild” less severe traumatic brain injury.