Reviewed and revised 6/5/2012
Normal swallowing requires: timing and coordination of many muscles and several cranial nerves which are under voluntary and involuntary nervous control.
- oral preparatory – mastication and creation of a food bolus
- oral transit – delivering the bolus to the back of the tongue + soft palate elevation
- pharyngeal – most complex with pharyngeal constriction to created a dynamic pressure gradient, breath-holding, elevation of the arytenoids, cord adduction and epiglottic inversion.
- oesophageal stage – with coordinated contraction and relaxation of oesophageal sphincter and peristaltic waves carrying bolus