Mechanism of traumatic petechial hemorrhages in the brain--neurovascular friction.

Abstract

I N CLOSED injuries of the brain, the most important and common pathological finding consists of petechial hemorrhages of various kinds plus neuronal injury. The cause of this kind of hemorrhage is not yet clearly understood. Some advocate that these hemorrhages might be the result of vasoconstriction, and others vasodilation and/or direct damage to the vascular walls in the brain. Gross 1 had the idea of intracerebral cavitation; Rowbotham 3 thought shear strain at the moment of blow might be the cause of these hemorrhages. Minkowski, 2 in 1930, first introduced the idea of to explain the traumatic changes in the brain. He thought, from a simple theoretical standpoint, that between all the intracranial structures, such as the cerebrospinal fluid and cerebral substance, the cortex and the medulla, the nerve cell and the surrounding tissue, the wall of the vessel and the surrounding tissue, the blood and the wall of the vessel and so on, should be the cause of various kinds of traumatic changes in the brain. From the clinical and pathological viewpoint, the authors suspected that between the wall of the vessel and the surrounding cerebral tissue at the moment of impact would cause this hemorrhage (Fig. 1). This we would term friction or neurovaskul~re Verschiebung. The neurovascular might occur in the following way. 1) Intracranial vessels are fixed either at the base of the skull or at a dural sinus, while the substance of the brain is soft, floating in the cerebrospinal fluid. ~) The strain and shift that these different, structures undergo vary at the moment of impact. To test this hypothesis, we conducted a series of experiments using dogs and monkeys.