Digestive System

Foreign objects can become stuck in the throat or esophagus for a number of reasons.  If the object is a piece of food, it can become stuck in the throat because chewing and swallowing  are not coordinated. One of the most important things to realize is that when food is being chewed, the airway to the trachea is not closed off by the epiglottis. Thus, breathing is possible. In order to swallow, we must temporarily stop breathing. Therefore, in order to eat effectively, we must coordinate breathing, chewing, and swallowing.

Lack of coordination of swallowing, chewing, and breathing is quite common in infants and young children, people who are elderly, and people who have diseases of the nervous system, such as Parkinson's disease.  Because young children and infants have not perfected chewing and swallowing, they are less likely to coordinate these movements with breathing. Specifically, infants are more likely to breathe in while they are swallowing food than adults. Elderly people are more likely to breathe in before and after they have swallowed. People who have impairments of the nervous system are more likely to swallow while they breathe in. As a result, the epiglottis may not close fully and the food may enter the trachea.

The type of food and how well it is chewed may also influence whether it becomes stuck in the throat.  Food that is small and spherical, such as nuts, are more likely to become lodged in the trachea. When food is chewed in the mouth, it is formed into a bolus. Because a bolus is mixed with saliva, it is slippery and able to travel through the esophagus. However, if the food is not chewed thoroughly, the bolus may not be formed adequately.

A person's ability to form a bolus can be influenced by a number of factors. For instance, the second molars in children under the age of 3 years old often do not have an adequate ability to grind food. Therefore, young children can be less able to form the food into a bolus. Similarly, older people who do not use dentures or have implants may have fewer teeth with which to chew the food. If they have their natural teeth, the enamel on their teeth may be thinner and their gums may recede. The muscles involved in chewing may also be weaker. Therefore, elderly people are less likely to chew their food thoroughly and may have difficulties forming the bolus. Also, some people with diseases of the muscle or nervous system may lack the strength, control, or feeling in their mouth. As a result, they are less likely to chew the food until it is ready to be swallowed, and the food may fall directly into the trachea.

Food may become stuck in the esophagus because the muscles involved in peristalsis action or the sphincters are not working correctly.  In this case, the food may remain in the esophagus.  One such condition is achalasia. In patients with achalasia, the esophageal muscles cannot move food into the stomach adequately. Therefore, the cardiac sphincter stays closed and the food remains in the esophagus.