Figure 7.

A diagram (in gray) of the two-sling mechanism, consisting of dashed lines and a solid line connecting large dots, is superimposed over an illustration of relevant anatomical structures. The three dashed lines represent skeletal levers including the cranial base (contiguous with the hard palate), mandible, and vertebrae mapped by 5 coordinates (mandible, posterior edge of hard palate, tubercle of the atlas, C2, C4). The solid gray line connecting large dots represents interconnected features of the hyolaryngeal complex mapped by four coordinates (hyoid, anterior commissure of the vocal folds, posterior commissure of the vocal folds, and the location of the upper esophageal sphincter). Each coordinate maps an element of the two-sling mechanism. Each of the yellow arrows indicates the relative magnitude and direction of covariation of each coordinate during swallowing in a cohort of young healthy normal subjects.