Title: Hyoid bone fusion and bone density across the lifespan: prediction of age and sex
Legend: Hyoid bone fusion rank definition (left panel) with images showing the same fusion rank bilaterally. The 3D Hyoid bone models (middle panel) were created using image visualization and analysis software Analyze 11.0 (AnalyzeDirect; Overland Park, KS). The CT scan axial slice (right panel) with the smallest distance between the hyoid body and the greater cornua was used for fusion ranking.
Citation: Fisher, E., Austin, D., Werner, H., Chuang, Y.J. Bersu, E. and Vorperian, H.K. (2016). Hyoid bone fusion and bone density across the lifespan: prediction of age and sex. Forensic Science, Medicine and Pathology, 12:146-157. NIHMSID: NIHMS781359. DOI 10.1007/s12024-016-9769-x
Abstract: The hyoid bone supports the important functions of swallowing and speech. At birth, the hyoid bone consists of a central body and pairs of right and left lesser and greater cornua. Fusion of the greater cornua with the body normally occurs in adulthood, but may not occur at all in some individuals. The aim of this study was to quantify hyoid bone fusion across the lifespan, as well as assess developmental changes in hyoid bone density. Using a computed tomography imaging studies database, 136 hyoid bones (66 male, 70 female, ages 1-to-94) were examined. Fusion was ranked on each side and hyoid bones were classified into one of four fusion categories based on their bilateral ranks: bilateral distant non-fusion, bilateral non-fusion, partial or unilateral fusion, and bilateral fusion. Three-dimensional hyoid bone models were created and used to calculate bone density in Hounsfield units. Results showed a wide range of variability in the timing and degree of hyoid bone fusion, with a trend for bilateral non-fusion to decrease after age 20. Hyoid bone density was significantly lower in adult female scans than adult male scans and decreased with age in adulthood. In sex and age estimation models, bone density was a significant predictor of sex. Both fusion category and bone density were significant predictors of age group for adult females. This study provides a developmental baseline for understanding hyoid bone fusion and bone density in typically developing individuals. Findings have implications for the disciplines of forensics, anatomy, speech pathology, and anthropology.
About the lab: The Vocal Tract Development Laboratory (VTLab) uses a combination of imaging, acoustics, and vocal tract modeling to understand the lifespan changes of the vocal tract anatomy in typically and atypically developing individuals, and to examine the relation of anatomic changes to speech acoustics.