Brain herniation

A herniation (English: herniation ) in medicine refers to the displacement of parts of the brain by increased Intracranial pressure. A distinction is made upper and lower incarceration. In the upper pinching it comes to the displacement of brain mass in the tentorium cerebelli. In the lower entrapment the cerebellar tonsils through the foramen magnum, an opening in the skull with connecting to the spinal cord, between the medulla oblongata and bony structures are pressed. Thus, the Extended spinal cord is compressed. If the respiratory center located there is affected, death results from respiratory failure. Therefore, the lower entrapment is immediately life-threatening, in contrast to the upper.

Course

The entrapment represents the final common pathway of disease of the brain that are associated with an increase in volume. The pathophysiology proceeds as follows: Due to the increased Intracranial pressure, the veins are compressed first, and later the arteries. It only comes to ischemia, then to a hemorrhagic infarction, it represents the actual mechanism which causes the damage of the neurons. The strangulation preceded vegetative symptoms such as increased blood pressure and increased respiratory rate. Furthermore, it leads to a constriction of the pupil, the miosis. This is a result of ischemia of the Edinger - Westphal nucleus, which increases its spontaneous discharge frequency due to the lack of oxygen and thus brings about the oculomotor nerve, the miosis. Only in the further course of cell death in the core area to a dilation of the pupil, mydriasis. Later, when herniation of the medulla oblongata, it comes to arterial hypotension.