déglutition

Déglutition, or swallowing, is a complex sensorimotor process that moves saliva, liquids and solids from the mouth to the stomach. It requires coordinated action of the oral cavity, pharynx, larynx, and esophagus, as well as the neural networks that control them.

The process is classically divided into four phases. The oral preparatory phase involves chewing and mixing the material with saliva to form a cohesive bolus; this phase is voluntary. The oral phase propels the bolus posteriorly toward the oropharynx through tongue movement. The pharyngeal phase is rapid and largely reflexive: the bolus triggers a swallow that closes the airway, elevates the larynx, and opens the upper esophageal sphincter to direct the bolus into the esophagus. The esophageal phase uses peristaltic contractions to transport the bolus to the stomach, with the lower esophageal sphincter relaxing to permit entry.

Neural control combines sensory input from the oropharynx with brainstem and cortical centers. A central pattern generator in the medulla coordinates the motor commands to the muscles involved, with cranial nerves V, VII, IX, X and XII playing major roles, supplemented by other pathways for timing and coordination.

Dysphagia, or difficulty swallowing, is a common clinical concern and can arise from stroke, neurodegenerative diseases, head and neck cancer, structural abnormalities, or age-related changes. Evaluation includes bedside swallow assessment, videofluoroscopic swallow study, and fiberoptic endoscopic evaluation of swallowing. Management focuses on safety, efficiency, and nutrition, employing compensatory strategies, rehabilitative therapy, texture modification, and, when necessary, enteral feeding.