The walls of the laryngopharynx consist of inner (longitudinal) and outer (circular) muscular layers. They are responsible for maintaining the airways and the propulsion of food and liquid.
External layer
The external circular layer collectively contains the pharyngeal constrictors:
- Superior pharyngeal constrictor
- Middle pharyngeal constrictor
- Inferior pharyngeal constrictor
Description
The constrictors, as per their name, cause sequential constriction of the pharynx, propelling food into the esophagus. These muscles surround the pharynx posteriorly and laterally, and they are oriented circularly around the pharynx.
- Although they are oriented circularly, they are actually longitudinal in direction.
- The constrictor muscles insert on eachother at the midline, forming a pharyngeal raphe.
- The inferior pharyngeal constrictor can be divided into two separate muscles; the thyropharyngeus and cricopharyngeus muscles.
- Their internal internal fascia, the pharyngobasilar fascia is strong and thick,