Swallowing, or deglutition, is a complex biological action that most individuals perform hundreds of times a day without conscious thought. This process involves the precise coordination of over 50 pairs of muscles in the mouth, throat, and esophagus. The tongue is the primary muscular organ responsible for manipulating food and initiating the swallow reflex. The question of whether this function can be executed without the tongue delves into the biomechanics of eating and the body’s remarkable capacity to adapt to anatomical changes. Understanding the mechanics of a typical swallow reveals why the tongue is important to the entire sequence.
The Three Phases of Swallowing
The entire process of moving food from the mouth to the stomach is divided into three sequential phases, transitioning from voluntary control to involuntary reflexes.
The first is the oral phase, the only stage under conscious, voluntary control. During this phase, food is chewed, mixed with saliva, and formed into a cohesive mass called a bolus in preparation for transit.
The second stage, the pharyngeal phase, begins when the bolus moves into the throat, triggering an involuntary reflex. This rapid, reflexive stage involves the elevation of the soft palate to prevent food from entering the nasal cavity. The larynx is closed by the epiglottis to protect the airway. Pharyngeal constrictor muscles then contract sequentially to propel the bolus downward toward the esophagus.
The final stage is the esophageal phase, which is entirely involuntary and transports the bolus to the stomach. Peristalsis, a wave-like muscular contraction, moves the food through the esophagus. This stage concludes when the lower esophageal sphincter relaxes, allowing the food to enter the stomach. The pharyngeal and esophageal phases are generally unaffected by the absence of a tongue because their muscular actions are reflexive.
The Critical Role of the Tongue in the Oral Phase
The tongue’s function centers on two main mechanical actions: bolus formation and anterior-to-posterior propulsion. First, the tongue works with the cheeks and palate to shape the food into a manageable, cohesive mass suitable for swallowing. This shaping process prevents the food from being too loose, which could lead to premature spillage into the throat.
The second action is generating the positive pressure needed to push the bolus backward toward the pharynx. The tongue achieves this by pressing against the hard palate in a progressive, wave-like motion from front to back. This compression creates the pressure gradient that drives the food mass until the involuntary pharyngeal reflex is triggered. Without this coordinated lingual action, initiating the swallow is a significant biomechanical challenge.
Swallowing Without the Tongue The Answer and Compensatory Actions
The direct answer to whether a person can swallow without a tongue is yes, but the process is profoundly altered and difficult, particularly with solid foods. Individuals who have undergone a total glossectomy, the surgical removal of the entire tongue, lose the ability to perform the crucial propulsive action of the oral phase. While the involuntary pharyngeal and esophageal stages remain intact, the body struggles to effectively deliver the food bolus to the point where the reflex is activated.
To overcome this mechanical deficit, patients develop compensatory mechanisms, often with the help of swallowing therapists. One common strategy is using a head-back posture, where the individual tilts their chin up to utilize gravity to transport the bolus backward toward the throat.
The remaining muscles of the mouth, such as the buccinator muscles in the cheeks, are engaged to narrow the oral cavity and assist in pushing the food mass posteriorly. The hard palate and the residual tissue in the floor of the mouth are also used to generate some pressure against the bolus. These actions aim to trigger the pharyngeal phase earlier than normal, often resulting in a functional, though not normal, swallow. Studies show that while these strategies are effective, they frequently require multiple swallows for a single bolus and carry a higher risk of complications.
Practical Challenges and Assistance for Eating
The absence of the tongue introduces oropharyngeal dysphagia, which is difficulty moving food from the mouth into the esophagus. The primary clinical concern is the risk of aspiration, where food or liquid enters the trachea and lungs due to insufficient airway protection. Aspiration can lead to serious respiratory complications, including pneumonia.
To manage these risks, patients must adopt a modified diet, often consisting of pureed foods or thickened liquids that are easier to control and transport. Thicker consistencies move slower, giving the body more time to achieve proper airway closure before the food passes. In severe cases, patients may require nutritional support through non-oral means, such as a percutaneous endoscopic gastrostomy (PEG) tube, which delivers nutrients directly to the stomach.
Swallowing rehabilitation is a standard part of recovery, involving speech-language pathologists who teach specific therapeutic maneuvers. Techniques like the supraglottic swallow or the Mendelsohn maneuver are practiced to improve the timing and strength of airway closure and pharyngeal muscle contraction. Specialized prosthetic devices, like a palatal augmentation prosthesis, can also be fitted to reshape the roof of the mouth, effectively lowering the palate to help the remaining oral structures generate the necessary pressure for bolus propulsion.