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In TBI, primary injuries result immediately from the initial trauma. Primary injury occurs at the moment of trauma and includes contusion, damage to blood vessels, and axonal shearing, in which the axons of neurons are stretched and torn. The blood brain barrier and meninges may be damaged in the primary injury, and neurons may die. Cells are killed in a nonspecific manner in primary injury. Tissues have a deformation threshold: if they are deformed past this threshold they are injured. Different regions in the brain may be more sensitive to mechanical loading due to differences in their properties that result from differences in their makeup; for example, myelinated tissues may have different properties than other tissues. Thus some tissues may experience more force and be more injured in the primary injury. The primary injury leads to the secondary injury.
Read more about this topic: Primary And Secondary Brain Injury
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