[Ring fractures of the base of the skull]

An Autopsy-Based Analysis of Fatal Road Traffic Collisions: How the Pattern of Injury Differs with the Type of Vehicle

In Italy, in only 2018, 3310 people died in road traffic accidents, more than in any other European country. Since the revelation of this occurrence, the authors carried out an analysis aimed at investigating if there was a difference in the injury patterns among different road users. A retrospective post-mortem study on road traffic fatalities was performed, which had been autopsied at the Institute of Forensic Medicine of Milan. First, the authors analyzed the epidemiological data of all the 1022 road traffic accidents subjected to an autopsy from 2007 to 2019. Secondly, further analysis of individual autopsy reports was carried out. For this purpose, 180 autopsies belonging to 5 different categories were analyzed: car, pedestrian, motorbike, bicycle, and truck. Seventy-six percent of road traffic fatalities were male, 54% were between 10 and 49 years of age, and 62% of the patients died before arriving at a hospital. “Multiple injuries” was the main cause of death. Traumatic brain injuries were particularly high in pedestrians and cyclists. In car, motorbike, and truck fatalities, thoracic and abdominal injuries were the most frequent. Therefore, pedestrians and cyclists had a higher prevalence for traumatic head injuries, while car, motorcycle, and truck occupants, on the other hand, had a higher prevalence for thoracic and abdominal injuries.

Research in forensic neurotraumatology

Over the past 100 years forensic research in neurotraumatology was focusing on the genesis, e.g. biomechanis, and the origin of epidural, subdural, subarachnoidal, intracerebral and brain stem haemorrhage, particularly under aspects to enable the differential diagnosis of bleeding due to non-traumatic diseases. Moreover the estimation of the age of brain injuries has important criminological implications (survival time following traumatic forces to the head, alibi etc.). Beside these main fields of research, aspects of expertise in special areas such as head trauma due to child abuse, capability to act despite severe brain injuries and research on cervical trauma are reviewed.

Longitudinal brainstem laceration associated with complex basilar skull fractures due to a fall: an autopsy case

This report describes an autopsy case of a rare longitudinal brainstem laceration associated with complex basilar skull fractures. The victim was a 40-year-old male who died immediately after falling from a roof (9.2m in height) of a factory onto a concrete floor. The postmortem examination revealed an incomplete ring fracture of the base of the skull with longitudinal fractures of the sphenoid (clivus of the dorsum sellae turcicae) and occipital bones, cerebral contusions in the frontal and temporal poles, a longitudinal brainstem laceration at the posterior median sulcus of the pons accompanied with multiple contusional hemorrhages in the brainstem and corpus callosum. Related blunt-force injuries were observed in the parieto-occipital region of the head, shoulder and upper back involving the fractures of the cervical and thoracic vertebrae, and sternum and ribs, indicating a huge impact to the occiput and subsequent impression of the vertebral column into the base of the skull due to violent anteroflexion of the neck, which caused the complex basilar skull fractures, contusions and longitudinal laceration of the brainstem.

Forensic pathological observations on fatal injuries to the brain stem and/or upper cervical spinal cord in traffic accidents

A retrospective study was performed on 149 forensic autopsy cases (12 in Kanazawa and 137 in Munich) of brain stem and/or upper cervical spinal cord (UCSC) injuries as a result of traffic accidents. Pedestrians were the most common type of victims, followed by car drivers. Eleven of the 12 Kanazawa victims were pedestrians. The total ratio of pedestrian victims gradually increased with age. The ponto-medullary junction was the most frequently injured site. A total of 146 cases demonstrated basal skull fractures and/or dislocation of the upper cervical joints: atlanto-occipital joint, atlanto-axial joint, or the joint between the 2nd and 3rd cervical vertebrae. However, in three cases, hyperextension of the neck unexpectedly caused brain stem injury neither associated with basal skull fracture nor with cervical dislocation. Intraventricular haemorrhage was found in 96 cases, suggesting a common feature associated with brain stem and/or UCSC injury. A tear of the basilar artery and that of the carotid artery was found in 17 and 20 cases respectively. A total of 39 victims demonstrated a blood alcohol concentration of over 0.5 mg/ml, and hyperextension of the neck occurred more frequently in these cases. In spite of the marked predominance of immediate death (138 cases), 11 cases (nine of brain stem injury and two of UCSC injury) had unexpected survival times of from 45 min to 12 h.

Ring fracture of the base of the skull and atlanto-occipital avulsion due to anteroflexion on motorcycle riders in a head-on collision accident

This report concerns a head-on collision accident of a motorcycle at a very high speed (c. 80-100 Km/h) against a bonnet-type automobile, in which both the motorcyclist and pillion rider were injured at the base of the skull by violent anteroflexion of the head due to the force of inertia. A difference in their injuries was: the motorcyclist sustained a 'ring' fracture and the pillion rider an atlanto-occipital avulsion; dural tear. Anteroflexion without impact on the occiput such as described above seems to be a rare causal mechanism of the 'ring' fracture. In addition, the mode of action of the accelerating forces to the heads of the victims along with their physiques may explain the mechanism which caused the different injuries in this accident.

[Forms of fractures of the occipital condyles]

In contrast to the large fracture system of the base of the skull, little attention has so far been paid to fractures of the occipital condyles. The mechanics of these fractures have mostly been described in the form of case reports. Here an attempt is made to classify fractures of the occipital condyle based on the literature and our own material. Fractures of the condyles in the sense of bursting or the injuries themselves are classified under the following forms of strain: 1. Axial compression (Jefferson type) condylar impression; 2. Axial traction (hangman's type) condylar retraction; 3. Rotation with axial strain condylar retraction; 4. Oblique compression (bursting fracture of the abutment) frontal condylar fracture; contralateral; 5. Oblique traction (horizontal thrust); a tearing at the base of the skull as in a contralateral condylar horizontal fracture; 6. Transverse thrust (longitudinal fracture of the base of the skull) partial condylar avulsion The functional connection between a longitudinal clivus and condylar fracture is illustrated by typical examples. Furthermore, the elliptical deformation model for a burst fracture at the base of the skull in the longitudinal axis is extended by the deeper transverse thrust stabilization of the condyles.