Swallowing

Swallowing chewed food initiates one of the body’s essential functions, digestion. Swallowing (deglutition) moves chewed food from the mouth through the pharynx and esophagus to the stomach. It is a complex action involving not only the tongue but also all muscles of the oral cavity, face, larynx, and esophagus.

Swallowing begins with jaw clenching, while the tongue forcefully presses the food bolus against the hard palate, pushing it into the pharynx. Contraction of pharyngeal muscles creates high pressure, forcing the bolus into the esophagus. Contrary to ancient beliefs, food does not fall into the stomach by gravity but is propelled by esophageal muscle contractions in wave-like motions.

The most critical moment of swallowing is when food reaches the pharynx. While the oral cavity serves both digestive and respiratory systems, the pharynx is their junction. From the pharynx, air passes through the larynx into the trachea and lungs, while food travels via the esophagus to the stomach. Swallowing is designed to prevent food from entering the airways, controlled by a dedicated brain center.

Swallowing is largely involuntary, with only the initiation under conscious control. Once food reaches the pharynx and esophagus, the process continues independently of will. Any disruption in transporting food from the mouth to the stomach is called dysphagia, commonly referred to as difficulty swallowing, which can result from changes (inflammation, tumors) in the oral cavity, pharynx, larynx, or esophagus.

Patients experience swallowing difficulties in various ways, sometimes with pain, which may be mild or absent. Issues are described as itching or burning during swallowing; some report food entering the trachea or nose. Swallowing problems may accompany speech, chewing, or breathing difficulties or occur only when swallowing solid food or liquids.

Pain during swallowing is most often caused by inflammation of the pharynx or esophagus. Painful swallowing is a constant symptom of nearly every acute pharyngeal inflammation, with varying intensity, sometimes feeling like a foreign body in the throat. Tonsillitis (angina) is a common cause of pain that worsens sharply with swallowing, accompanied by fever and general weakness.

Severe pain is caused by burns from swallowing hot food or liquids or inhaling hot air, accompanied by hoarseness and, in severe cases, breathing difficulties or choking. Even more intense pain results from swallowing strong acids or alkalis, known as chemical injuries or burns of the pharynx and esophagus.

Excruciating pain and fear at the mere thought of swallowing are early signs of rabies, appearing three weeks to three months after a bite from a rabid animal. Once symptoms appear, rabies is incurable, preventable only by timely vaccination within days of the bite.

Almost everyone has choked at least a few times in their life. A piece of food may reach or enter the trachea, typically expelled by strong coughing. Older adults choke more often due to uncoordinated swallowing muscle activity from changes in brain swallowing centers, arteriosclerosis, or reduced brain blood supply.

If a foreign object enters the airways and isn’t expelled by coughing, the person should be placed in a lying position. Calm breathing can keep the object in the main airway. Standing or heavy breathing may dislodge it into deeper lung areas. Such individuals should be transported to a hospital lying down. Small inhaled objects that remain in deeper airways can cause severe pneumonia, known as aspiration pneumonia.

Sudden death during swallowing, called bolus death, is not uncommon. In the U.S., choking on food is the sixth leading cause of accidental death, surpassing deaths from firearms or plane crashes.

Choking and death occur when a food bolus or object lodges in the back of the pharynx or between the vocal cords, completely blocking the airway. The victim cannot speak or breathe, turns pale, soon becomes cyanotic (blue), and loses consciousness within seconds. Often, the person freezes, eyes bulging, or runs in panic before collapsing unconscious and dying before onlookers.