Final answer:
The pharyngeal constrictor muscles originate from structures like the pterygoid hamulus, mandible, hyoid bone, and laryngeal cartilages, and they attach to the posterior median raphe of the pharynx. Coordinated contraction of these muscles during swallowing moves the food bolus into the esophagus, under the control of the vagus nerve.
Step-by-step explanation:
Pharyngeal Constrictor Muscles
The pharyngeal constrictor muscles play a vital role in the process of swallowing, or deglutition, by moving the food bolus from the pharynx into the esophagus. There are three pharyngeal constrictors: the superior, middle, and inferior. The site of origin of these muscles is variable and includes the pterygoid hamulus, mandible, hyoid bone, and cartilages of the larynx. For example, the superior constrictor originates from the pterygoid hamulus and mandible, the middle constrictor from the hyoid bone, and the inferior constrictor from the thyroid and cricoid cartilages. They all attach to the posterior median raphe of the pharynx. The coordinated contraction of these muscles constricts the pharyngeal space, propelling the food bolus into the esophagus.
Their action is essential for the act of swallowing and they are innervated by the vagus nerve (Cranial Nerve X) which orchestrates their activity in concert with other muscles of the oropharynx and esophagus. The importance of the pharyngeal constrictor muscles is further highlighted during the pharyngeal phase of swallowing, where they work alongside other muscles to ensure the bolus moves safely past the respiratory pathways and into the digestive tract.