Forensic Pathology for Police - Brainshare Public Online Library

318 12 Blunt Force Injury Deaths
quickly the death occured. This last point is especially important. In numerous cases
of death due to blunt force head trauma, the only intracranial injuries that are evident
at autopsy include subdural and subarachnoid hemorrhage. None of the other
injury types described below are evident. In these cases, it is presumed that some of
these brain injuries actually occured, but because death occured so quickly, they are
not evident by gross or microscopic examination. In this regard, subdural and subarachnoid
hemorrhage may be considered “markers” or indicators that lethal brain
trauma may have occurred.
As with other organs and tissues, the brain can be lacerated. As with lacerations
elsewhere, brain lacerations are evident as splitting apart of the brain substance.
These injuries can be difficult to identify at autopsy, often because there are numerous
other injuries, such as contusions. Extensive lacerations may ultimately result in
avulsion injuries. The usual situation where brain avulsion occurs involves severe,
open skull fractures. In infants, lacerations from blunt force injuries may be more
common than contusions, whereas in older individuals, contusions are much more
common.
Brain contusions represent areas of hemorrhage within the brain resulting from
trauma. There are several different types of brain contusions, based on location
and/or mechanism of injury. Many contusions occur right at the surface of the cerebral
cortex (the “crests” of the gyri), in areas closest to the overlying skull. Grossly,
they appear as multiple, relatively small (several millimeters long), linear areas of
hemorrhage with the long axes perpendicular to the surface of the brain (Fig. 12.23).
Frequently, there is associated overlying subarachnoid hemorrhage. Cerebral contusions
commonly occur immediately underlying a skull fracture site, and are referred
to as “fracture” contusions. If a cerebral contusion occurs directly under a scalp
impact site (without an associated fracture), the cerebral contusion is referred to as
a “coup” contusion but if it occurs in a location opposite from the side of impact,
the injury is referred to as a “contrecoup” contusion. Both coup and contrecoup
Fig. 12.23 Multiple cerebral cortical contusions in a formalin-fixed brain