Pharyngeal achalasia

The craniopharynx consists of the upper esophageal sphincter muscle (UESM), the pharynx, the pharyngeal muscle, the upper circular muscle of the esophagus, and the cartilage-like hypopharynx and circular cartilage. The sensation and movement of the UESM and the cyclopharyngeal muscle are dominated by the sensory fibers of the glossopharyngeal nerve and the voluntary motor fibers of the vagus nerve. So swallowing can start as you like, or it can be reflexively caused by oropharyngeal stimulation. In the resting state, the UESM is in a tense state. When swallowing, the food contracts strongly through the mouth, tongue, and pharyngeal muscles, pushing the esophagus to the pharynx, UESM relaxes, and the esophagus contracts after entering the esophagus. This process is about 0.3s (0.13 to 0.63s). After swallowing, the esophagus body has a peristaltic contraction, which is pushed into the stomach after 0.5 to 1 s and then closed. Therefore, swallowing movement is the result of the concerted action of relaxation and contraction of the hypopharynx, UESM, esophagus body and lower esophageal sphincter muscle (LESM). If the swallowing and its relaxation are not coordinated during swallowing, it is difficult for the esophagus to enter the esophagus from the pharynx, causing difficulty in swallowing, that is, pharyngeal muscle achalasia, also known as esophageal spasm.