June 8, 2022 Swallowing belongs to digestion and aims to move the food bolus from the mouth to the stomach. It is a complex mechanism, which involves multiple and quick actions, in which several muscle groups intervene, coordinated by 5 cranial nerves, which, in turn, are commanded by the brain centers. The integrity of all these structures is essential for normal swallowing. Swallowing has 3 phases : Oral or buccal : movement of the food bolus from the mouth to the oropharynx; Pharyngeal : movement of the food bolus from the oropharynx to the esophagus; Esophageal : movement of the food bolus from the esophagus to the stomach. The oral phase of swallowing is voluntary (it depends on will), but the rest are involuntary. In the pharyngeal phase, the first of the involuntary phases, the mechanism that prevents food from entering the larynx (respiratory system) during swallowing is triggered: the larynx rises 2 cm, the base of the tongue descends, the epiglottis tilts down and the cords vocals close the entry of the airway. Exception for babies, in humans the airway and digestive tract are not separated. Therefore, the aforementioned mechanisms are necessary to prevent the diversion of food to the respiratory system (entry into the larynx) during swallowing. In babies, the higher position of the larynx separates the two systems and allows eating and breathing simultaneously. In the esophageal phase of swallowing, that is also involuntary, the food bolus moves from the esophagus to the stomach, mainly due to the contraction and relaxation of muscles in the esophageal wall that create the so-called peristaltic movements. The muscles above the food bolus contract and this contraction propagates and pushes the food bolus. Simultaneously, the muscles below the bolus relax, facilitating its movement. Dysphagia Dysphagia means alteration or difficulty in swallowing . Dysphagia can be associated with any of the swallowing phases mentioned, depending on the structures that have their function compromised. So, dysphagia can be: Oropharyngeal , related to the oral and pharyngeal phases of swallowing; Esophageal , related to difficulty in passing the bolus into the esophagus. Oropharyngeal dysphagia is still a poorly recognized problem, often underestimated and rarely diagnosed. Often it is even undervalued by the person himself, but it can have serious consequences. When not treated timely, life-threatening aspiration pneumonia can be a complication when food or liquids are passed into the respiratory tract. Thus, persistent symptoms such as pain, coughing or choking when swallowing, accumulation of saliva in the mouth , even if mild, should not be underestimated. The d iagnosis and treatment must be carried out by the action of a specialized multidisciplinary team that also aims to raise the awareness of the other professionals involved. When to see an otolaryngologist Medical care from an otolaryngologist should be sought when there are swallowing disorders: In the context of an oncological disease or sequelae of its treatment; In states after stroke or traumatic brain injury ; Associated with degenerative diseases, neurological diseases, laryngeal paralysis ; In situations of weight loss , malnutrition , frequent choking , or possibility of aspiration pneumonia (with alert for cough and fever, even if low). This article was written by the otorhinolaryngology team at Hospital da Luz. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
