Abstract
Deglutition is the transfer of solids and liquids from the oral cavity to the stomach brought by complex coordinated reflex action. This action is divided into three stages, the oral, the pharyngeal and the esophageal stage. Once the swallow has begun, all the essential muscles participate in a stereotyped way, especially in the pharyngeal stage.
This paper deals with the effect of the anesthesia and the kind of bolus in the pharyngeal stage of swallowing in dogs, studied with electromyography.
In these series of investigations, operative exposure was followed by implanting a 0.12mm surgical stainless steel wire electrodes for electromyographic testing into the three elevators of the larynx, geniohyoid muscle mylohyoid muscle and thyrohyoid muscle, the four pharyngeal constrictors, palatopharyngeal muscle, hyopharyngeal muscle, thyropharyngeal muscle and cricopharyngeal muscle, one puller back of the tongue base styloglossal muscle and the three intrinsic laryngeal muscles, thyroarytenoid muscle, posterior cricoarytenoid muscle and cricothyroid muscle.
Electromyographic recording was usually done at least one day after the operation, the animal being conscious or in light anesthetic condition by Ketaral®. The delay time from the kinetic activity of the geniohyoid muscle to the cricopharyngeal muscle and the relaxation time of the cricopharyngeal muscle and the cricothyroid muscle in the anesthetized dog were about two times as long as in the conscious condition.
The delay time and the relaxation time of the electromyogram were also longer in the dry solid swallowing than in the liquid swallowing.
