Hyolingual Kinematics and Biplanar Videoradiography Reveal Hydrostatic Deformation of the Tongue Base
Session Number
Project ID: BIO 04
Advisor(s)
Peishu Li
Dr. Callum Ross, University of Chicago
Discipline
Biology
Start Date
17-4-2024 8:35 AM
End Date
17-4-2024 8:50 AM
Abstract
Tongue base retraction (TBR) is the action of the tongue being pulled backwards and shortened and is vital to swallowing in mammals. Compromised TBR performance leads to patients having more food residue in the pharynx, posing more risks for choking. However, the biomechanical mechanisms driving TBR remain poorly understood. The muscular hydrostat hypothesis posits that the hydrostatic deformation related to the contraction of intrinsic muscles lengthens the tongue base. The extrinsic muscle shortening hypothesis suggests that structures surrounding the tongue, the hyoglossus and styloglossus, pull the tongue base. In this study, we evaluated the role of intrinsic and extrinsic structures in TBR through nine swallows of one opossum, a model system for mammalian feeding physiology. We measured tongue and hyoid movement during swallowing using biplanar videoradiography following the XROMM workflow. Using CT scans to visualize the hyolingual anatomy of opossums, we found that opossums do not have a styloglossus. In vivo observation of marker movement falsifies the hypothesis that extrinsic muscles shorten to produce TBR. Our data supports the intrinsic muscle hypothesis as in vivo tongue base deformation pattern is consistent with the muscular hydrostat model. Our findings may facilitate new treatment exercises during rehabilitation for poor tongue base retraction.
Hyolingual Kinematics and Biplanar Videoradiography Reveal Hydrostatic Deformation of the Tongue Base
Tongue base retraction (TBR) is the action of the tongue being pulled backwards and shortened and is vital to swallowing in mammals. Compromised TBR performance leads to patients having more food residue in the pharynx, posing more risks for choking. However, the biomechanical mechanisms driving TBR remain poorly understood. The muscular hydrostat hypothesis posits that the hydrostatic deformation related to the contraction of intrinsic muscles lengthens the tongue base. The extrinsic muscle shortening hypothesis suggests that structures surrounding the tongue, the hyoglossus and styloglossus, pull the tongue base. In this study, we evaluated the role of intrinsic and extrinsic structures in TBR through nine swallows of one opossum, a model system for mammalian feeding physiology. We measured tongue and hyoid movement during swallowing using biplanar videoradiography following the XROMM workflow. Using CT scans to visualize the hyolingual anatomy of opossums, we found that opossums do not have a styloglossus. In vivo observation of marker movement falsifies the hypothesis that extrinsic muscles shorten to produce TBR. Our data supports the intrinsic muscle hypothesis as in vivo tongue base deformation pattern is consistent with the muscular hydrostat model. Our findings may facilitate new treatment exercises during rehabilitation for poor tongue base retraction.