| Abstract: | Basing on the review of the foreign and domestic literature the point of view concerning the anatomical structure, innervation and histomorphology of the pharyngoesophageal segment (pes) is being presented. Special attention was paid to the impact of the somatic and autonomic (particularly its sympathetic part) nervous system on the function of the pharynx, as well as the pressure at rest with the pharyngoesophageal sphincter. Histomorphologic investigations suggest that the pes function and tension of the particular pharyngeal constrictors (upper, middle and inferior) is determined by: a) structure, b) distribution of the IX and X nerve fibre ends in pharyngeal sphincters, c) structure of the pharyngeal sphincter, which is also supplied with the nervous fibre ends of the upper cervical sympathetic trunk. The sympathetic trunk is located on both sides of vertebral column from the skull base till the tip of the sacral bone. In case of degenerative process in the neck segment of the vertebral column, irritation of the sympathetic part of the autonomic system is taking place. Experimental investigations revealed that the stimulation of the sympathetic nervous fibres of the autonomic system results in weakening of the upper and middle pharyngeal sphincter's tension and increase of tension in its lower part (cricopharyngeal muscle). This can be an etiopathogenic factor under physiological condition in disturbances of the pharyngeal phase of deglutition act. After total laryngectomy, however, high pressure in the lower part of the pes (in the area of pharyngoesophageal sphincter) renders it difficult or even impossible to introduce the air into the esophagus to master the phonation and esophageal speech. The significance of the knowledge of the pes innervation in clinical practice is important for prognosis in mastering of supplementary, esophageal and shunt phonation. |
