Differences in geometry between human (A,B) and rodent (C,D) swallowing anatomy, in the oropharyngeal conduit through which the bolus is transported (A,C) and in the orientation of the muscles involved in propulsion and transport of the bolus. Anatomical landmarks to characterize swallowing mechanics in human (CASM; B) and rodent (CASM-R; D) map muscle groups involved in tongue, jaw, and pharyngeal displacement.