On the mechanics and topography of thyroid cartilage fractures

K. S. Saternus, R. B. Dettmeyer, R. Amberg, C. G. Birngruber,

Abstract: Introduction. For the evaluation of violent force to the neck, osseous injury patterns of the larynx play an important role. A thorough investigation of fracture patterns may allow reconstructive statements in autopsy cases as well as in clinical forensic cases. Materials and methods. Preparatively (autopsy) and radiologically (x-ray images, equidensity images) documented cases of thyroid cartilage fractures were selected. Selection criteria were the diagnoses of ligature strangulation, manual strangling, lethal ligature/ manual strangling and shaped blunt force to the neck. The fracture patterns in the thyroid cartilage plates were related to the type of ossification and compared to theoretically expectable fracture patterns. Results. Depending on the manner of force application and ossification, five different types of thyroid cartilage fracture patterns can be distinguished: type I is a paramedial sagittal longitudinal fracture resulting from a ventrally applied plane force (ligature strangulation); type II is a segmental fracture resulting from a medial point load (shaped blunt force); type III is a lateral sagittal longitudinal fracture from bilateral point load (manual strangulation); type IV is an intermediary segmental fracture resulting from central point load (manual strangulation); and type V is a break-out fracture of the inferior cornu resulting from lateral point load (manual strangulation). With combinations of ligature and manual strangling, corresponding fracture types can coincide. Conclusions. Manual and ligature strangling can lead to distinguishable types of fracture in the thyroid cartilage. Thereby these types of fracture gain a diagnostic significance for the forensic-autoptical and clinical analysis of force to the neck.
Keywords: thyroid cartilage fracture, manual strangling, ligature strangling, classification, bio-mechanics.