Development of the hyoid‐larynx complex and its variants: significance for clinical and forensic studies (17.7)

Anatomical variations of the hyoid‐larynx complex occur in 4‐28% of the general population. The embryonic development of this complex, however, has been poorly described, and it is unclear whether current descriptions, which form the basis for the explanation of the development of these variants, are based on observations of original human embryos or on comparative embryology. To obtain more insight in the development of the hyoid‐larynx complex, we analyzed histological sections of human embryos from the Carnegie Collection. Three‐dimensional models were prepared in a novel interactive portable format providing crucial spatial information and facilitating interpretation. Furthermore we analyzed a forensic‐radiological database with 300 dedicated scans of the hyoid‐larynx explantates. In contrast to current theories, we observed that the body of the hyoid bone originates from a single growth center, without overt contributions from the second and third pharyngeal arch cartilages. The thyroid and cricoid cartilages develop from mesenchymal packaging, instead of pharyngeal arch cartilages. Most variants are not important in a clinical setting, however they are important in forensic setting if a fracture of the hyoid bone is suspected. In those cases it is of utmost importance to discern between a fracture of the hyoid bone or the thyroid horns and malfusion of those parts.