Experimental brain damage from fluid pressures due to impact acceleration. 3. Morphological observations.

"Contre-coup" lesions occurring particularly in the frontal and temporal lobes following head injury have been claimed to be caused by sudden negative pressure transients, as part of the "contre-coup" end pressures occurring in the brain tissue at an occipital impact. With a new experimental model such impact acceleration pressure (near-1 atm) could be generated in the rabbit brain through a parietal opening. Resulting morphological changes were evaluated with various microscopical methods, including Evan's blue-albumin technique for observations on vascular permeability changes. Regardless of the magnitude of the negative pressure transients no changes characteristic of "contre-coup" lesions were seen in temporal lobes, i.e. in areas where preparative artefacts are absent in control animals. Therefore such negative pressure transients per se do not appear to be of major importance for the development of contre-coup lesions. However, vascular permeability changes were frequently observed in the brain stem and upper cervical cord and are presumably related to the flow of tissue in the cranio-spinal junction.