Hemorrhagic lividity of the neck: controlled induction of postmortem hypostatic hemorrhages.

Postmortem hypostasis (livor mortis or lividity) is classically defined as the intravascular pooling of blood in gravitationally dependent parts of the body after death. However, intense lividity can be associated with small hemorrhages in the skin, so-called postmortem hypostatic hemorrhages (Tardieu spots). Postmortem hypostatic hemorrhages seem to contradict the usual understanding of lividity, since hemorrhage is by definition an extravascular phenomenon. Substantive medicolegal difficulties can arise if such hemorrhagic lividity develops in the necks of bodies that have ventral lividity due to prone position at the death scene. To study this phenomenon, we have developed a model for the controlled formation of hypostatic hemorrhages in human cadavers. In this model, extensive hypostatic hemorrhages or hemorrhagic lividity could be reproducibly but not universally induced in the soft tissues of the anterior neck and strap muscles. Histologic examination revealed hemorrhage that was microscopically indistinguishable from the acute hemorrhages observed in contusions. In addition, some larger areas of interstitially extravasated blood showed "buffy coat"-sedimentation separation of neutrophils that closely mimicked acute inflammation, further confounding the correct diagnosis. This research implies that hypostatic hemorrhages form after the progressive development of increasing gravitational hydrostatic pressure in an autolysing venous plexus. Thus, this phenomenon can mimic soft tissue injury ("pseudo-bruising") and the internal injuries related to strangulation. Caution must be exercised when diagnosing strangulation in bodies with anterior neck lividity.