Physiology of swallowing

The mechanism behind normal swallowing is complex and multifactorial. Due to the close proximity of the pathways of swallowing and respiration, precise coordination between these functions is vital in order to avoid entry of material into the airway and to ensure optimal health and nutrition in general. Swallowing can be divided into three stages: oral, pharyngeal and oesophageal, and although initiation of the swallow is often under voluntary control, swallowing is also triggered frequently throughout the day as a reflex action due to the presence of saliva in the oropharynx. Dysphagia is a symptom frequently encountered by clinicians and its causes are vast and varied. A thorough understanding of the physiology of swallowing remains necessary to conduct a full assessment and instigate appropriate treatment for these patients in whom dysphagia is often debilitating and may significantly affect their quality of life. We present an account of the physiology of swallowing, illustrated with clinical examples.