Middle pharyngeal constrictor muscle
The middle pharyngeal constrictor is a fan-shaped muscle located in the neck. It is one of three pharyngeal constrictor muscles. It is smaller than the inferior pharyngeal constrictor muscle. The middle pharyngeal constrictor originates from the greater cornu and lesser cornu of the hyoid bone, and the stylohyoid ligament. It inserts onto the pharyngeal raphe. It is innervated by a branch of the vagus nerve through the pharyngeal plexus. It acts to propel a bolus downwards along the pharynx towards the esophagus, facilitating swallowing. StructureThe middle pharyngeal constrictor is a sheet-like, fan-shaped muscle.[1] The muscle's fibers diverge from their origin: the more inferior fibres descend deep to the inferior pharyngeal constrictor muscle; the middle portion of fibres pass transversely; the more superior fibers ascend and overlap the superior pharyngeal constrictor muscle.[1] OriginTwo parts of the middle pharyngeal constrictor muscle are distinguished according to its sites of origin:
InsertionThe muscle inserts (posteriorly) into the pharyngeal raphe,[1] blending with its contralateral partner at the midline.[citation needed] InnervationSimilarly to the superior and inferior pharyngeal constrictor muscles, it is innervated by a branch of the vagus nerve through the pharyngeal plexus.[citation needed] Actions/movementsThe contraction of the muscle constricts the middle portion of the pharynx.[1] FunctionThe muscle contracts during swallowing:[1] as soon as the bolus of food is received in the pharynx, the elevator muscles relax, the pharynx descends, and the constrictors contract upon the bolus, and convey it downward towards the esophagus.[2][3] They also have respiratory mechanical effects.[4] Additional images
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