![]() It acts as a sphincter at the lower end of the pharynx and is always closed except for momentary relaxation during swallowing. ![]() Its muscle fibers are continuous with the circular muscular coat of the esophagus. Its fibers run continuously from one side of the cricoid arch to the other side around the pharynx without inserting into a midline raphe posteriorly. The cricopharyngeus muscle is rounder and thicker than the other constrictor muscles. The lower fibers are horizontal and lie edge to edge with those of the cricopharyngeus component. Its fibers curve around posteriorly and insert into the midline raphe. Function Īs 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, conveying it downward into the esophagus.The thyropharyngeus muscle arises from the (a) thyroid cartilage at the oblique line and (b) the tendinous arch that spans the cricothyroid muscle. Actions/movements Ĭonstriction of the muscle constricts the superior portion of the pharynx. The superior fibers arch beneath the levator veli palatini muscle and the Eustachian tube. There is an interval between superior pharyngeal constrictor and middle pharyngeal constrictor, this space contains glossopharyngeal nerve, lingual nerve and the stylopharyngeus muscle. The interval between the upper border of the muscle and the base of the skull is closed by the pharyngeal aponeurosis, and is known as the sinus of Morgagni. Vasculature Īrterial supply is provided primarily by the pharyngeal branch of the ascending pharyngeal artery, and the tonsilar branch of the facial artery. The superior pharyngeal constrictor muscle receives motor innervation from the pharyngeal plexus of vagus nerve. The muscle's fibres extend posterior-ward from its origin to form the midline pharyngeal raphe which then attaches onto the pharyngeal tubercle (of the basilar part of the occipital bone). Glossopharyngeal part - a few fibers originating from the side of the tongue.Mylopharyngeal part - originating from the alveolar process of the mandible above the posterior end of the mylohyoid line.Buccopharyngeal part - originating from the pterygomandibular raphe.Pterygopharyngeal part - originating from the lower third of the posterior margin of the medial pterygoid plate and its hamulus.įour parts of the muscle are distinguished according to the origin: The sites of origin of the muscles collectively are the pterygoid hamulus (and occasionally the adjoining posterior margin of the medial pterygoid plate) anteriorly, (the posterior margin of) the pterygomandibular raphe, the posterior extremity of the mylohyoid line of mandible, and (negligibly) the side of the tongue. It is thinner than the middle and inferior constrictor muscles. The superior constrictor muscle is a quadrilateral, sheet-like muscle. It acts to convey a bolus down towards the esophagus, facilitating swallowing. It is innervated by pharyngeal branch of the vagus nerve via the pharyngeal plexus. The muscle inserts onto the pharyngeal raphe, and pharyngeal spine. The muscle is divided into four parts according to its four distincts origins: a pterygopharyngeal, buccopharyngeal, mylopharyngeal, and a glossopharyngeal part. It is the uppermost and thinnest of the three pharyngeal constrictors. The superior pharyngeal constrictor muscle is a quadrilateral muscle of the pharynx.
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