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

Pontomedullary lacerations and concomitant head and neck injuries: their underlying mechanism. A prospective autopsy study

It is a well-documented fact that pontomedullary lacerations (PML) occur as a result of severe craniocervical injury, but their underlying mechanism has yet to be fully clarified. The aim of this prospective study has been to give greater insight into the underlying mechanism of PML through determining the site of blunt head-impact, as well as the presence of concomitant head and neck injuries in cases of brainstem PML. A total of 56 cases with partial PML have been analysed for this study. The case group was composed of 40 men and 16 women, averaging in age 44.2 ± 19.2 years and consisting of 7 motorcyclists, 4 bicyclists, 18 car occupants, 16 pedestrians, and 10 victims of falls from a height, as well as 1 victim of a fall from standing height. The presented study has shown that there are several possible mechanisms of PML. Impact to the chin, with or without a skull base fracture, most often leads to this fatal injury, due to the impact force transmission either through the jawbone or vertebral column; most likely in combination with a fronto-posterior hyperextension of the head. Additionally, lateral head-impacts with subsequent hinge fractures and PML may also be a possible mechanism. The jawbone and other facial bones are able to act as shock absorbers, and their fracture may diminish the energy transfer towards the skull and protect the brain and brainstem from injury. The upper cervical spine can act as damper and energy absorber as well, and may prevent any occurrence of fracture to the base of the skull.

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.

Decapitation in suicidal hanging--a case report with a review of the literature

We report a case of self-decapitation by suicidal hanging from a river bridge and discuss the decapitation mechanism, reviewing the literature. The torso and the head of the victim, respectively, were found apart in a river approximately 100 m and 600 m, respectively, downstream from the bridge in two days. Morphological, serological and DNA analyses confirmed their identity. Torn ligaments between the atlas and axis accompanied by fractures in the axis at the partes interarticulares were indicative of a traction force combined with anteroflexion of the head by falling from a height, and the radial pressure due to a strong, single twisted nylon rope with a slip knot was considered to have contributed considerably to the subsequent skin laceration with wavy marginal abrasions. In the reviewed literature, cervical spine fractures were described only in two of six cases, suggesting head movement at the time of decapitation.

Radiologic spectrum of craniocervical distraction injuries

Injuries to the atlanto-occipital region, which range from complete atlanto-occipital or atlantoaxial dislocation to nondisplaced occipital condyle avulsion fractures, are usually of critical clinical importance. At initial cross-table lateral radiography, measurement of the basion-dens and basion-posterior axial line intervals and comparison with normal measurements may help detect injury. Computed tomography (CT) with sagittal and coronal reformatted images permits optimal detection and evaluation of fracture and luxation. CT findings that may suggest atlanto-occipital injury include joint incongruity, focal hematomas, vertebral artery injury, capsular swelling, and, rarely, fractures through cranial nerve canals. Magnetic resonance (MR) imaging of the cervical spine with fat-suppressed gradient-echo T2-weighted or short-inversion-time inversion recovery sequences can demonstrate increased signal intensity in the atlantoaxial and atlanto-occipital joints, craniocervical ligaments, prevertebral soft tissues, and spinal cord. Axial gradient-echo MR images may be particularly useful in assessing the integrity of the transverse atlantal ligament. All imaging studies should be conducted with special attention to bone integrity and the possibility of soft-tissue injury. Atlanto-occipital injuries are now recognized as potentially survivable, although commonly with substantial morbidity. Swift diagnosis by the trauma radiologist is crucial for ensuring prompt, effective treatment and preventing delayed neurologic deficits in patients who survive such injuries.