Comparative Anatomy of the Hyoid Apparatus in Various Dog Breeds: Insights From Clinical Imaging

Studying the hyoid bone in dogs is of significant importance in veterinary surgery and anatomy, as it aids in understanding how variations in this structure may affect tongue mobility, swallowing and vocalisation across breeds.

This study aims to provide preliminary insights into the relationship between structural differences in the hyoid bone and breed-specific functional adaptations in tongue shape and movement by analysing shape variations within the hyoid apparatus.

Hyoid bones from computed tomography images of 26 dogs were modelled, and principal component analysis (PCA) was conducted to examine shape variation in the hyoid bones. Additionally, the influences of age and weight on hyoid bone shape were assessed.

PCA showed that PC1 (42.4%) reflected a relatively conservative pattern related to hyoid and skull morphology, whereas PC2 and PC3 indicated greater individual variation. Brachycephalic breeds exhibited a more dorsoventrally positioned and compact hyoid structure, while mesocephalic breeds showed a more aligned and elongated configuration of the stylohyoid and thyrohyoid bones. No significant correlations were found between hyoid shape and age, weight or Procrustes distance, suggesting a stronger influence of genetic factors.

Understanding the morphological variation of the hyoid bone in dogs contributes to veterinary anatomy and has practical applications in veterinary medicine, particularly in surgical and rehabilitation practices. Given the hyoid apparatus's critical role in swallowing and vocalisation, insights from this study may enhance clinical approaches to treating conditions linked to hyoid bone morphology.