The middle pharyngeal constrictor forms the oropharyngeal muscular wall, with its fibres overlapping both the superior and inferior constrictors to create a continuous muscular tube. The sequential constrictor contraction produces the peristaltic wave of the pharyngeal swallowing phase. Zenker's diverticulum (pharyngeal pouch) forms at Killian's dehiscence, the gap between the middle and inferior constrictors where the thyropharyngeus fibres of the inferior constrictor cross.
| Origin | Greater and lesser horns of the hyoid and lower part of the stylohyoid ligament |
|---|---|
| Insertion | Median pharyngeal raphe — fibres spread upward (overlapping superior constrictor) and downward (overlapping inferior constrictor) |
| Nerve Supply | Pharyngeal plexus (IX and X) |
| Blood Supply | Lingual and ascending pharyngeal arteries |
| Actions | Constricts the middle pharynx (oropharynx level) during the pharyngeal phase of swallowing; Creates the sequential peristaltic wave that propels the food bolus toward the oesophagus |
|---|
Killian's triangle (between the oblique thyropharyngeus and horizontal cricopharyngeus fibres of the inferior constrictor) is the point of least resistance where Zenker's diverticulum herniates. The diverticulum's treatment targets the cricopharyngeus (the dysfunctional sphincter) by myotomy during open or endoscopic Zenker's repair.
Not palpable from the surface.
Posterior pharyngeal herniation through Killian's dehiscence from cricopharyngeal dysfuction producing dysphagia and regurgitation managed with endoscopic or open cricopharyngeal myotomy.
