Morphological Investigation of the Roe Deer ( <i>Capreolus capreolus</i> ) Os Hyoideum and Creating a 3D Model

The os hyoideum, located at the intersection of the respiratory and digestive tracts, holds strategic importance due to its role in breathing, swallowing and vocalisation. The morphological structure of the os hyoideum varies among species. Since no research has been found on the hyoid bone in the roe deer (Capreolus capreolus), this study was planned. Six roe deer os hyoideum were used. The bones forming the os hyoideum were examined macroscopically and histologically, with morphometric measurements taken from 28 parameters. Additionally, the roe deer os hyoideum was 3D modelled and printed using TPU filament. The hyoid bone, connected to the skull by syndesmosis, consists of six parts: basihyoideum, thyrohyoideum, ceratohyoideum, epihyoideum, stylohyoideum and tympanohyoideum. While the tympanohyoideum is entirely compact bone, the middle of the other parts is compact bone and the ends are spongy bone. Among the joints between the parts, the tympanohyoideum-stylohyoideum and basihyoideum-thyrohyoideum joints are synchondrotic, while the others are synovial. In the roe deer, stylohyoideum was the longest part at 42.56 mm, while tympanohyoideum was the smallest at 6.92 mm. When the os hyoideum was printed using TPU filament, each bone part maintained its structural integrity. This study provided detailed morphological and morphometric data on the roe deer os hyoideum for the first time. The absence of proc. lingualis in the basihyoideum and the general morphological resemblance to carnivora in roe deer were noteworthy.