The brain itself is made of soft, Jello-like tissue. It’s not a fixed, hardened structure like you find in bones. The brain consists of millions of very fine nerve fibers and floats around inside a hardened skull, in cerebral-spinal fluid. When the head is suddenly struck or is violently shaken or strikes a solid stationary object, the utter force of this motion goes directly to the brain.
When the head rotates during trauma, the brain inside also moves, twists and turns and undergoes forces that cause the brain-matter to move. Sudden movements of the head or forces directly hitting the head cause the brain tissue to move although the brain is protected within the skull and is highly resilient. This type of motion stretches, squeezes and may even tear the neural brain cells. To maintain the precise distance between neural cells and the delicate balance needed to effectively process and send messages between cells requires a calm, stable environment. When brain cells are squeezed and stretched due to these kinds of forces this delicate balance is altered and this can easily cause problems in the brain’s processing of information.