Figure 1.

Four stages of deglutition (swallowing). (A) During food chewing, depression of the soft palate (dark blue) helps close the oropharyngeal isthmus, the gate between the oral cavity and oropharynx. (B) During swallowing, the soft palate is elevated and touches the posterior pharyngeal wall. At this point, the oropharyngeal isthmus is open. (C) The soft palate stops the breath “traffic” and directs food into the laryngopharynx. (D) Finally, the food enters into esophagus (modified from Lieberman 2011).