Experimental fracture investigations concerning the hyoid bone fracture.

INTRODUCTION: Extensive literature exists concerning the etiology and morphology of fractures of the hyoid bone (h.b.) in cases of fatal strangulation. There is an agreement to the effect that fractures are mostly located within the distal third of the cornua majora (c.m.). Although several predictors have been described very accurately, the fracture analysis has neither been based on the osseous construction nor on the stress distribution of the c.m. under strangulation resulting from the configuration and its details. This especially applies to the apex of the distal ends of the big horns, the bulbi. The objective of the experimental break tests that were performed was to contribute to elucidating the biomechanics of the horizontal and vertical fractures and to fractures of the bulbi. MATERIALS AND METHODS: Break tests in the a.p. direction line were carried out on 28 unfixed h.b. of adults on a specially constructed test bench by continuously increasing the tension until a fracture/dislocation occurred. The test arrangement followed the constellation of typical-symmetrical hanging. The selection criteria were the symmetry of the h.b. and the gender. Before and after the experiments, a radiological depiction (DIMA system 20 kV, 10 sec; Institute for Diagnostic Radiology, University-Hospital Goettingen) was carried out, followed by a preparative depiction under magnifying glass control. The h.b. configuration was classified according to the following types: hyperbole-, parabola-, and horseshoe-type. Following this classification, the results were related to the findings achieved by the photo-elastic model experiments. By this, the results of the experimental fracture tests could be specifically compared to the tension distribution within the model. RESULTS: A total of 70 % of the experimentally-produced fractures were located within the distal third of the c.m. This matches with the frequency distribution in real typical symmetrical hanging. Following the radiological and preparative investigations that were carried out, the c.m. have to be viewed as tubular bones. The transition regions of different osseous strength/elasticity are thus to be considered as areas of increased vulnerability. For the distal third of the c.m., it is the level at which the dense spongiosa/compacta of the shaft part turn into wide-meshed spongiosa and tender compacta of the bulbi. Additionally, the bulbi themselves represent a locus of reduced strength in which the fractures were located basally and/or apically in the transition. It was not only in the whole c.m. that the direction in which the fragment was snapped off or fractured was not random, as all fractures were located on the broad side of the horn, following the applied force. CONCLUSIONS: The experimental fracture tests explained the known accumulation of fractures in the distal third of the c.m. in cases of hanging with the knot of the rope located against the neck. It could be demonstrated radiologically and preparatively that, anatomically, the big horn of the h.b. is a tubular bone. From this, a new approach to the forensic reconstruction of trauma can be derived. The transitional area from the shaft into the bulbus represents a locus minoris resistentiae. In case of pressing the h.b. towards the cervical spine under ventral application of force, one could expect a point load of the bulbi. Two different types of bulbus fractures showed that this load is diagnostically relevant. The fracture direction is also of diagnostic value. It depends on the angle that is formed by the c.m. with their broad side towards the horizontal. This angle may even change for about 90° for the c.m. in the course from proximal to distal movement. By adjustment of the alignment of the broad side with the stress distribution within the different types of the h.b., a mechanically justified answer can be given to the question of why a horizontal fracture appears in the one case and a vertical fracture in the other.

Unilateral and bilateral agenesis of the upper thyroid horns - A morphometric analysis of the larynx.

The agenesis of one or both upper thyroid horns (UTH) cannot be considered rare with an incidence ranging between 0.8-9.4%. Studies so far have mostly described frequencies, yet surveys on its morphology and traumatology are missing. It is unknown to what extent this anatomical variant impacts the overall symmetry of the larynx. For the trauma reconstruction after cervical trauma this knowledge is required as an asymmetric larynx can show a different fracture pattern. In this investigation, larynxes with unilateral (n=21)/bilateral (n=5) agenesis of the upper thyroid horn(s) and a control group with regular larynxes (n=23) were juxtaposed. Various measurements were taken after µ-CT scanning. In total 10 distances/angles for the thyroid cartilage and 8 for the cricoid cartilage were compared. Using intra-individual and matched pair comparisons the symmetry was assessed. The results of this investigation showed significant differences in the intra-individual and pairwise comparison for the opening angle and the length of the thyroid alae although the lateral inclination of the thyroid alae showed no significant difference. Combining these three parameters into one symmetry score, the comparison was not significant. This research demonstrates that neither unilateral nor bilateral agenesis of the UTH is related to a structural disbalance of the larynx. Thus, different fracture patterns or vulnerabilities are not to be expected.

A functional polymorphism in the tyrosine hydroxylase gene indicates a role of noradrenalinergic signaling in sudden infant death syndrome.

OBJECTIVES: Catecholamines may contribute to the cause of sudden infant death syndrome (SIDS). TH01, a tetrameric short tandem repeat marker in the tyrosine hydroxylase gene, regulates gene expression and catecholamine production. STUDY DESIGN: We investigated TH01 in 172 German Caucasian SIDS cases and 390 sex- and age-matched control subjects. RESULTS: The *9.3 alleles were more frequent in patients with SIDS than in control subjects (40.12% vs 31.15%; P = .006). For homozygotes the odds ratio was 1.83 (95% confidence interval: 1.09-3.05), for carriers 1.58 (1.09-2.28). Moreover, *9.3 alleles were significantly more frequent during the winter (47.73% vs 35.38% in the warmer seasons), and the frequency of *9.3 alleles varied significantly with the age at death (weeks 7 to 12: 49.04% vs 29.63% within the first 6 weeks). Other risk factors (sleeping position, gestation, smoking) had no significant impact on the frequency of *9.3. CONCLUSIONS: Our results indicate a relationship between SIDS and TH01 genotype, presumably caused by an impairment of breathing regulation or arousal. We propose that noradrenalinergic neuronal activity contributes to the cause of a major subset of SIDS victims. Moreover, the results further stress that SIDS is a highly heterogenic group.

Shaken baby syndrome: re-examination of diffuse axonal injury as cause of death.

The discussion surrounding shaken baby syndrome (SBS) arose from the lack of evidence implicating diffuse axonal injury (DAI) as a cause of death. It was assumed instead that injury to the cervical cord, medulla, and nerve roots played a causal role. The present pathomorphological study examines 18 selected infants (<1-year-old) whose deaths were highly suspicious for SBS, exhibiting the classical SBS triad of acute subdural hemorrhage (SDH), retinal bleeding, and encephalopathy. Gross autopsy and microscopic findings of these infants were compared with those of 19 victims of sudden infant death syndrome (SIDS; control group 1) and of 14 infants who died of disease or injuries/violence not involving the head, neck or eyes (control group 2). Symptoms of mechanical impact to the head were evident in seven of the SBS infants, but in none of the control infants. DAI was not detected in either the SBS or control cases. Localized axonal injury (AI) was regularly present in the brains of the SBS infants surviving longer than 1.5-3.0 h, but only occasionally in the craniocervical junction and within the nerve roots of the upper cervical cord; it was never present in the medulla. Epidural hemorrhage of the cervical cord was seen in four of the ten examined SBS cases, but in none of the control cases. Based on the absence of DAI in the brain and of signs of generalized cervical cord or nerve root injuries, we conclude that the cause of death in the SBS victims was a global cerebral ischemia secondary to SDH, focal vasospasm, trauma-induced transitory respiratory and/or circulatory failure.

Fatal outcome of varicella in children.

Varicella or chicken-pox are one of the most frequent diseases in childhood. Severe or even lethal complications are rare (in about 0.03 per thousand ). Our paper presents two cases of varicella infections leading to sudden deaths (3- and 7-year-old children). In one of these cases, the paediatrician in charge was accused of an impaired medical treatment. Both of the children showed multiple typical efflorescences in different stages. Furthermore were observed affections of the respiratory tracts and serious involvements of the hearts, the lungs, and the livers. In one case an immunological identification could be made of an acute varicella infection. Based on autoptical, histological, bacteriological, virological, and neuropathological findings is given an analysis of such uncommon and severe courses of chicken-pox in children being identified as haemorrhagic form and massive abscess-forming varicella pneumonia.