Timing of events within the pharyngeal swallow

Time line showing volume-induced modifications in the timing of events within the pharyngeal swallow. Each horizontal bar depicts the period during which one of the oropharyngeal valves is in a swallowing configuration as opposed to a respiratory configuration. Events at the onset and offset of pharyngeal reconfiguration bear a fixed time relationship to each other, regardless of swallow bolus volume. The stereotypy of these phases is demonstrated by referencing of onset events from time 0 counting forward and of offset events from time 0 counting forward or backward. This timing scheme defines the volume-dependent middle portion of the time line (black), which has a value of 0 for 1-mL swallows and 0.2 seconds for 20-mL swallows.