Event data recorders in the analysis of frontal impacts.

Evaluations of crash protection safety features require measures for quantifying impact severity. Velocity change (delta-V) is the major descriptor of collision severity used in most real-world crash databases. One of the limitations of delta-V is that it does not account for the time over which the crash pulse occurs (delta-t). Late model GM vehicles equipped with event data recorders capture the cumulative delta-V in 10 ms intervals over the crash pulse. Deceleration can be readily calculated from these data and provides a complementary measure of severity that has not previously been available for real world crashes. The relationship between maximum delta-V and deceleration was examined for different vehicle platforms involved in real world frontal impacts and frontal crash tests. Maximum deceleration was observed to be closely correlated to the maximum delta-V.

Mechanisms of aortic injury in fatalities occurring in motor vehicle collisions.

Case reviews based on autopsy studies have shown that motor vehicle collisions cause between 50 and 90% of traumatic aortic ruptures. Very few studies have analyzed the nature and severity of the collision forces associated with this injury. Our passenger car study (1984-1991) examined 36 collisions in which 39 fatally injured victims sustained aortic trauma. In this injury group, a disproportionate number of heavy truck and roadside fixed-object impacts occurred. Vehicle crash forces were generally severe and were either perpendicular or oblique to the vehicle surface. Intrusion into the occupant compartment was a significant factor in most of these fatal injuries. Occupant contact with vehicle interior surfaces was identified in most cases, and occupant restraints were often ineffective, especially in side collisions. The more elderly victims were seen in the least severe collisions. The most frequent site of aortic rupture was at the isthmus. A majority of victims had rib/sternal fractures indicating significant chest compression. Of the various traumatic aortic injury mechanisms proposed in motor vehicle impacts, the favored theories in the literature combine features of rapid deceleration and chest compression. This study supports that predominant impression, concluding that rapid chest deceleration/compression induces torsional and shearing forces that result in transverse laceration and rupture of the aorta, most commonly in the inherently vulnerable isthmus region.

Craniocervical injuries in judicial hangings: an anthropologic analysis of six cases.

Restoration projects and archaeologic excavations in two Canadian prisons resulted in the recovery of the skeletons of six felons executed by judicial hanging. Damage inflicted by hanging on various skeletal elements was observed. Among the injuries seen were fractures of the hyoid cornua, styloid processes, occipital bones, and cervical vertebral bodies (C2) and transverse processes (C1, C2, C3, and C5). Despite the general uniformity of the hanging technique, which involved a subaural knot, the trauma to the skeletal elements and the cause of death varied among individuals. Although some of this variation was probably due to minor differences in hanging practices, individual anatomic peculiarities of the victims likely also contributed.

Commercial logging fatalities in Ontario, 1986-1991.

Despite the economic importance and hazardous nature of commercial logging in various regions, few medical studies have examined fatalities in this industry. Data derived from the files of the Ontario Chief Coroner's Office revealed 52 deaths, all men, from 1986 to 1991 in the province of Ontario. Forty-four cases were accidents (age range 20-73 years; average, 44 years), the majority involving experienced loggers. Personal error resulting in preventable unsafe work practices was a factor in most accidents (n = 35; 79.5%). Almost one half of injured workers were struck by either dead or cut trees. Although the majority of cases occurred in remote areas, delayed medical attention as a factor contributing to death was uncommon. Many of the injuries were nonsurvivable and most victims (n = 33; 75%) were dead at the scene. Most deaths were caused by either head and neck injuries (n = 20; 45.5%), multiple trauma (n = 10; 23%), chest trauma only (n = 6; 13.5%), or mechanical asphyxia (n = 5; 11%). Blood alcohol was negative in 24 accident victims tested. Eight deaths (age range 42-52 years; average, 49 years) were due to cardiac causes, mainly ischemic heart disease. Disease may have contributed to two accidents.

Fatal light aircraft accidents in Ontario: a five year study.

Fatal civil aviation crashes in Ontario from 1985 to 1989 were studied. Data regarding accident circumstances, injury patterns and medical factors (disease, alcohol/drugs) which could have contributed to accident causation was obtained from a review of the files of the Chief Coroner for Ontario in Toronto and the aviation occurrence reports of the Transportation Safety Board of Canada. Forty-seven crashes involving mainly general aviation type aircraft but also 2 gyroplanes, 2 ultralights and a glider were reviewed. About half occurred during the cruise phase of the flight. Seventy (40 pilots; 30 passengers) of the 98 occupants died. The bodies of 68 victims were recovered; 63 were dead at the scene and 5 survived up to ten hours after impact. Multiple trauma killed about half of all the victims (n = 34); 29% (n = 20) drowned; 16% (n = 11) and 3% (n = 2) died of head/neck injuries and coronary disease respectively. Neck trauma was observed mostly in pilots and was the most frequent major blunt trauma injury in drowning victims. Passengers sustained relatively more craniofacial fractures and abdominal/retroperitoneal trauma. Pilot error was the most frequent cause of crashes (55%; 26/47 impacts) followed by mechanical failure (15%; 7/47) and adverse weather/environmental conditions (11%; 5/47). Coronary artery disease incapacitated two pilots (4% of crashes) and ethanol intoxication was implicated in two other accidents. Other drugs did not appear to be a definite factor in accident causation.

Homicidal blunt head trauma, diffuse axonal injury, alcoholic intoxication, and cardiorespiratory arrest: a case report of a forensic syndrome of acute brainstem dysfunction.

Sudden death can occur in drunk individuals who are severely beaten about the face. The structural basis for this forensic syndrome is unknown. We herein describe the case of an intoxicated 23-year-old man (blood alcohol 234 mg%, 51 mmol/l) who was involved in an altercation and received blows and kicks to his head. A cardiorespiratory arrest occurred during the assault. He was resuscitated in hospital 23 min later but died 90 h after admission of severe ischemic encephalopathy and bronchopneumonia. Postmortem examination revealed diffuse scalp bruising, no evidence of a skull fracture, multiple small hemispheric contusions, severe cerebral edema secondary to ischemic encephalopathy, and axonal swellings in the corpus callosum, subcortical white matter, midbrain, right rostral inferior cerebellar peduncle, and medulla. This case of near sudden death confirms that blunt head trauma sustained during an assault can cause mild diffuse axonal injury. In addition, it is possible that sudden, alcohol intoxication-associated, craniofacial traumatic death is caused by acute dysfunction of the brainstem cardiorespiratory centers, whose capacity to correct potentially fatal dysrhythmias or apnea, induced by injury to their afferent axons, can be compromised by alcohol ingestion.

Skull fractures in fatalities due to motor vehicle collisions.

A retrospective analysis of 89 fatalities with skull fracture resulting from motor vehicle-pedestrian and various single passenger car frontal, side, rear and rollover collisions was done. Passenger compartment intrusion and occupant ejection were responsible for most, but not all, cranial fractures occurring in impacted motor vehicles. Victims of frontal collisions usually were unrestrained; however, a majority of individuals in cars hit by heavy trucks were wearing seatbelts. Vehicles involved in frontal crashes had crush profiles reflecting a barrier equivalent velocity (BEV) of at least 50 km/h (about 30/mph). In side impacts, most ejected occupants were unrestrained, whereas many of those intruded upon were belted. The minimum BEV calculated in these collisions approached 20 km/h (12 mph). The observation of a skull fracture integrated with accident investigation (that is, determination of head contacts) was useful in the reconstruction of various collisions. Skull fracture patterns, as documented by autopsy, reflected certain kinematic trajectories described in motor vehicle-pedestrian frontal collisions.

Delayed rupture of spontaneous tear of the ascending aorta--report of two fatalities.

A spontaneous tear of the ascending aorta, with or without medial dissection, can cause sudden death from hemorrhage due to aortic rupture. Two representative cases are described. Review of the clinical history and pathological changes showed that the terminal event was delayed allowing healing and reactive changes to occur in the aortic wall. A pathologist confronted with a fatal case of aortic rupture should be aware that death is not always immediate. Recognition of this has medicolegal importance, particularly if medical management is questioned because of a missed clinical diagnosis.

Fire and suicide: a three-year study of self-immolation deaths.

Thirty-two self-immolation deaths by fire, representing about 1% of suicides, occurred in the province of Ontario (population 9 million), Canada, from 1986 through 1988. The victims, mostly male (male/female ratio, 26:6), were between 21 and 71 years old (mean age, 38 years). Although the scene of self-immolation was usually familiar to the deceased, some chose remote locations. Eleven were found dead in motor vehicles. An accelerant, usually gasoline, was used in most cases. Many of these individuals had, at some time, indicated their intent to commit suicide, a few by self-immolation, but only about half had a diagnosed psychiatric illness. Most of the victims had a reason to kill themselves, but the factors that motivated them to chose self-immolation by fire were uncertain. Fourteen individuals died in hospitals from severe burn complications. The remainder were found dead at the scene. The postmortem findings of soot in the airway and elevated carbon monoxide in the blood of most of these victims [the carboxyhemoglobin (COHb) concentration was in one case less than 10%, in ten cases greater than or equal to 10 to 50%, and in seven cases greater than 50%] were helpful in determining that the individuals were not only alive at the time of the fire but also that a significant number died from smoke inhalation and carbon monoxide poisoning. The highest levels of carbon monoxide were observed in victims discovered in motor vehicles.

Azygos vein laceration due to blunt trauma.

The azygos vein ascends along the thoracic spine through the mediastinum and drains into the superior vena cava at the level of the fourth thoracic vertebra. Fracture-dislocation of the mid-thoracic spine, as a result of blunt thoracic trauma, can tear the azygos vein. Four such fatal cases (three motor vehicle accidents and one fall) were studied, only one of which was recognized prior to death. The vein can also be torn, in the absence of skeletal injuries, by horizontal acceleration/deceleration forces. The pathologist must consider azygos vein laceration as a possible cause of either hemothorax or hemomediastinum or both in a victim of a blunt chest trauma, if that individual had persistent hypotension during the few hours before death and no identifiable source of hemorrhage can be found postmortem in sites such as the heart, great vessels, lung, and chest wall. A fracture-dislocation of the thoracic spine may not necessarily be present. Azygos vein laceration seems to be an uncommon cause of hemothorax and hemomediastinum; however, this injury is probably more frequent than is implied by the few cases described in the medical literature.

Upper cervical trauma in motor vehicle collisions.

Motor vehicle collisions can cause a variety of injuries in pedestrians and vehicle occupants. Fatal and nonfatal trauma to the upper cervical spine, that is, atlanto-occipital junction, atlas and axis, can be part of this spectrum. Certain distinctive injuries (for example, "hangman's fracture") which occur result from the unique anatomic structure of this area and the various disruptive forces such as extension, distraction (tension), compression (axial loading), shear, and inertia generated during collision. Correlation of autopsy findings or radiological information of these cervical injuries or both with scene investigation can be informative not only in the determination of morbidity and mortality, but also in the assessment of injury mechanisms and improvements in occupant protection.

Extra-adrenal myelolipoma.

Extra-adrenal myelolipomas are rarely reported lesions, with only 18 cases found in the world literature. We report a series of three cases, all occurring in women in an age range of 68 to 83 years (mean, 77 years). One patient presented with a pelvic mass while the other two cases were incidental findings at autopsy. All lesions were presacral in location, encapsulated, and not attached to adjacent structures. Sizes ranged from 6 to 12 cm in greatest dimension and from 72 to 330 g. Color was a variegated yellow to red-brown. Microscopically, all were composed of mature fat and focal collections of normal hematopoietic elements. The nature of these lesions is not known but most authors favor a choristomatous origin. They must be distinguished from extramedullary hematopoietic tumors seen in patients with severe anemias, myeloproliferative disorders, and skeletal disease.

Fatal iatrogenic salicylate intoxication in a long-term user of enteric-coated aspirin.

A 64-year-old woman, who was taking long-term enteric-coated aspirin therapy for rheumatoid arthritis, was prescribed approximately twice her normal dosage (7.1 g daily) during a ten-day convalescence following surgery. Although she presented with features mimicking sepsis, biochemical analysis, ie, a spuriously high carbon dioxide content, suggested salicylate intoxication (admission salicylate concentration, 5.13 mmol/L). She died on the third day after admission. Autopsy showed no major source of infection except for bronchopneumonia. Long-term users of a high-dose aspirin are at risk for potential salicylate intoxication. The metabolism of salicylate, particularly its excretion kinetics, can make small upward dosage adjustments hazardous. Salicylate has widespread metabolic effects that can mimic other medical conditions, leading to delayed diagnosis of salicylate intoxication. Increased mortality and morbidity may result.