There are four stages of a normal swallow. When one or more of the stages show anatomical deviations or physiological disturbances that affect a normal swallow, dysphagia occurs.
ORAL PREPARATORY STAGE
- Food is masticated (chewed)
- Food mixes with saliva, forming a cohesive food ball, called a bolus
- This stage can last up to 30 seconds depending on consistency of food to be masticated
- The tongue and soft palate (roof of your mouth) squeeze together, moving the bolus posteriorly
- This movement of the bolus in an anterior-posterior motion is often called lingual stripping.
- This stage should last only 1 - 2 seconds
- The bolus enters the upper throat area and the soft palate elevates
- The epiglottis descends as the larynx elevates, covering the airway
- Tongue moves posteriorly and meets with the pharyngeal wall which has bulged forward
- The elevation of the larynx pulls open a muscle at the top of the esophagus that allows the food to enter.
- This stage should last only 1 second
- The food enters the esophagus through the upper esophageal sphincter, and is transported to the stomach by the squeezing action of the esophageal muscles.