Preparation for swallowing. The bolus is confined in the oral cavity with lip closure anteriorly and the posterior tongue and soft palate in close approximation. 

Initiation of swallow. The bolus has passed into the oropharynx. The soft palate has apposed Passavant's cushion in the constrictor wall and thus closes the palatopharyngeal isthmus, preventing nasopharyngeal regurgitation. 

The bolus is contained in the oropharynx. The larynx has elevated and closed, and the epiglottis is in a horizontal position. 

The bolus is in the oropharynx and has entered the hypopharynx and adjacent esophagus. The epiglottis is tilted downward, and the peristaltic wave of the pharyngeal constrictor muscles is in the midpharynx.

The bolus has passed into the pharyngoesophageal segment (region of the cricopharyngeus muscle) and cervical esophagus. 

The bolus is disappearing into the upper esophagus. The laryngeal airway has reopened. The epiglottis has returned to the upright position. The cricopharyngeus muscle has returned to its resting state - contracted.