Laryngeal anomalies: Pitfalls in adult forensic autopsies

Clinical Anatomy and Medical Malpractice-A Narrative Review with Methodological Implications

Anatomical issues are intrinsically included in medico-legal methodology, however, higher awareness would be needed about the relevance of anatomy in addressing medico-legal questions in clinical/surgical contexts. Forensic Clinical Anatomy has been defined as "the practical application of Clinical Anatomy to the ascertainment and evaluation of medico-legal problems". The so-called individual anatomy (normal anatomy, anatomical variations, or anatomical modifications due to development, aging, para-physiological conditions, diseases, or surgery) may acquire specific relevance in medico-legal ascertainment and evaluation of cases of supposed medical malpractice. Here, we reviewed the literature on the relationships between anatomy, clinics/surgery, and legal medicine. Some methodological considerations were also proposed concerning the following issues: (1) relevant aspects of individual anatomy may arise from the application of methods of ascertainment, and they may be furtherly ascertained through specific anatomical methodology; (2) data about individual anatomy may help in the objective application of the criteria of evaluation (physio-pathological pathway, identification-evaluation of errors, causal value, damage estimation) and in final judgment about medical responsibility/liability. Awareness of the relevance of individual anatomy (risk of iatrogenic lesions, need for preoperative diagnostic procedures) should be one of the principles guiding the clinician; medico-legal analyses can also take advantage of its contribution in terms of ascertainment/evaluation.

Anthropological analysis of trauma in throat bone and cartilage: A review

In their analysis of recovered human remains, forensic anthropologists encounter structures of the throat (hyoid bone, thyroid cartilage/bone, cricoid cartilage/bone) that may present evidence of trauma. The recent published literature provides guidelines for the detection and interpretation of fractures in these tissues. Such traumatic injury frequently is associated with victims of hanging and strangulation, but many other causes have been recognized. Although the hyoid is not always recovered in skeletonized remains, it can reveal evidence of perimortem trauma and must be interpreted appropriately.

Injuries of the isolated larynx-hyoid complex in post-mortem computed tomography (PMCT) and post-mortem fine preparation (PMFP) - a comparison of 54 forensic cases

Objectives

To assess the diagnostic accuracy (ACC) of post-mortem computed tomography (PMCT) for fractures of the isolated larynx-hyoid complex (LHC) in comparison to post-mortem fine preparation (PMFP).

Methods

This monocentric prospective study enclosed 54 LHCs that were extracted during autopsy, fixed in formalin, and underwent a PMCT scan (64-row multidetector CT, helical pitch). Two radiologists independently analyzed the LHC scans for image quality (IQ) and fractures (4-point Likert scales). A specialized forensic preparator dissected the specimens under the stereomicroscope. The PMFP results were standardized documented, and used as the standard of reference for the comparison to PMCT.

Results

The PMCT-IQ of 95% of the LHC images was rated as good or excellent. IQ was decreased by decay, incisions during autopsy, and separation of the hyoid from the cartilaginous components in 7, 3, and 12 specimens, respectively. PMFP detected 119 fractures in 34 LHCs (63.0%). PMCT identified 91 fractures in 32 specimens (59.3%). PMFP and PMCT significantly agreed concerning the location (Cohen’s κ = 0.762; p < 0.001) and the degree of dislocation (κ = 0.689; p < 0.001) of the fractures. Comparing PMCT to PMFP resulted in a sensitivity of 88.2%, a specificity of 90.0%, and an ACC of 88.9% for the LHC. The ACCs for the hyoid, thyroid, and cricoid were 94.4%, 87.0%, and 81.5%, respectively. PMCT procedure was significantly faster than PMFP (28.9 ± 4.1 min vs. 208.2 ± 32.5 min; p < 0,001).

Conclusions

PMCT can detect distinct injuries of the isolated LHC and may promptly confirm violence against the neck as cause of death. PMFP outmatches PMCT in the detection of decent injuries like tears of the cricoid cartilage.

Key Points

• Post-mortem computed tomography is able to assess fractures of the larynx-hyoid complex.

• Prospective monocentric in vitro study showed that post-mortem computed tomography of the larynx-hyoid complex is faster than post-mortem fine preparation.

• Post-mortem computed tomography can confirm violence against the neck as cause of death.

Laryngeal anatomical variants and their impact on the diagnosis of mechanical asphyxias by neck pressure

The aims of this investigation were to determine the characteristics and prevalence of anatomical variants of the larynx apparatus and to evaluate the impact of these variants on the accurate diagnosis of laryngeal fractures. A population-based study was carried out, analyzing a series of 207 consecutive autopsied cases in the Institute of Legal Medicine of Galicia (Northwestern Spain). The prevalence of triticeal cartilage was 52.7% and that of agenesis of thyroid horns 10%. Calcification of the stylo-hyoid ligament accounted for 1.4%. We identified three new anatomical variants: the terminal segmentation of the thyroid horns (11.6%), ectopic superior thyroid horns (8%) and lateral thyrohyoid ossification (5.3%). These three names, based on anatomical criteria, are the author's proposal to solve the lack of uniformity in the designation of these variants. Agenesis of thyroid horns were related to the presence of ectopic superior thyroid horns in 93% of cases, either uni or bilateral. The combination of variants was present in 6.8% of the cases, being the terminal segmentation of the thyroid horns in association with triticeal cartilage the most frequent (3.8%). The probability of misdiagnosis due to the presence of anatomical variations in deaths by pressure on the neck was high in this population (71.5%). The prevalence of triticeal cartilage in more than half of the sample, determined an important rate of potential errors (46.4%), followed by the mistaken diagnoses induced by terminal segmentation of thyroid horns (7.3%) and by ectopic superior thyroid horns (6.3%). The likelihood of a misdiagnosed laryngeal fracture was greater if the thyroid cartilage was affected, with a higher proportion of false positives comparing to the hyoid bone (p<0.001). The higher frequency of thyroid fractures in neck pressure together with the prevalence and location of triticeal cartilage on the lower third of the lateral thyrohyoid ligament are the main reasons for these results. Further studies should be done with larger samples to expand epidemiological data and consolidate these results and their influence on the diagnosis of mechanical asphyxias.

The Laryngohyoid Complex in Medicolegal Death Investigations

The laryngohyoid complex, composed of the hyoid bone and laryngeal cartilages, can be of interest in the autopsy setting, particularly when injuries are observed. Analysis of trauma to this structure can assist in establishing cause and manner of death. In many situations, the forensic anthropologist, with their expertise in analyzing bone and cartilage trauma, can assist in analyzing trauma to this complex. Although researchers have tried to study the relationships between causes of trauma to the osseocartilaginous structure and the observed injury pattern, they have not been successful in identifying unique signatures associated with different causes of trauma. This is because different causes can result in the same or similar injury patterns. In addition, variation due to growth and development or due to remote injury may change the structure's biomechanical response. The goal of this paper is to address issues that a forensic pathologist may encounter when assessing potential trauma to the osseocartilaginous structures of the laryngohyoid complex; in particular, it focuses on anatomical variants and trauma resulting from various causes.

Micro computed tomography features of laryngeal fractures in a case of fatal manual strangulation

Cases of subtle fatal neck compression are often complicated by the lack of specificity of the post-mortem signs of asphyxia and by the lack of clear signs of neck compression. Herein we present a forensic case of a 45-year-old schizophrenic patient found on the floor of the bedroom of a psychiatric ward in cardiopulmonary arrest and who died after two days in a vegetative state. The deposition of the roommate of the deceased, who claimed responsibility for the killing of the victim by neck compression, was considered unreliable by the prosecutor. Autopsy, toxicological analyses, and multi-slice computed tomography (MSCT), micro computed tomography (micro-CT) and histology of the larynx complex were performed. Particularly, micro-CT analysis of the thyroid cartilage revealed the bilateral presence of ossified triticeous cartilages and the complete fragmentation of the right superior horn of the thyroid, but it additionally demonstrated a fracture on the contralateral superior horns, which was not clearly diagnosable at MSCT. On the basis of the evidence of intracartilaginous laryngeal hemorrhages and bilateral microfracture at the base of the superior horns of the larynx, the death was classified as a case of asphyxia due to manual strangulation. Micro-CT was confirmed as a useful tool in cases of subtle fatal neck compression, for the detection of minute laryngeal cartilage fractures, especially in complex cases with equivocal findings on MSCT.