TCRN Practice Exam 2026 – Complete Prep for Your Test

Diffuse axonal injury is primarily caused by shearing forces, which occur during rapid acceleration or deceleration, typically associated with traumatic brain injuries. When the head is violently shaken or subjected to a sudden stop, the brain moves within the skull, leading to tears and damage in the axons where they connect different brain regions. This type of injury is most commonly seen in scenarios such as car accidents or falls, where the forces cause the brain to move in a way that creates significant stretch and shear on the axonal structures.

In contrast, penetrating trauma involves an object breaching the skull and can cause focal injuries rather than diffuse ones. Blunt forces to the skull can lead to various types of brain injuries, including contusions and fractures, but they do not specifically result in the diffuse axonal injury seen with shearing forces. Thermal injuries, caused by extremes of heat, affect tissues in a different manner and are not associated with the mechanical shearing forces responsible for diffuse axonal injury. Thus, shearing forces are clearly the mechanism that leads to this type of injury.