Its development commences between the 4th and 7th week of gestation. Development Įmbryological origin is the third pharyngeal arch. Supernumerary muscles originating from other nearby regions of the skull may be present, and may be clinically significant. The glossopharyngeal nerve runs on the lateral side of this muscle, and crosses over it to reach the tongue. On the lateral pharyngeal wall, it is situated posterior to the superior constrictor muscle, and anterior to the buccopharyngeal fascia. Superior hyoid bone and glossoepiglottic and pharyngoepiglottic folds. The muscle is situated in between the external carotid artery and internal carotid artery. Posteriormiddle and inferior constrictor muscles, posterior pharyngeal mucosa supported by the vertebral bodies of C4C6, prevertebral fascia, and the retropharyngeal space. The stylopharyngeus is the medial-most and most vertical of the three styloid muscles. The lymphatic drainage of the region of the stylopharyngeus muscle is mediated by the middle cervical lymph nodes that drain into the supraclavicular lymph nodes. The stylopharyngeus receives arterial supply from the paryngeal branch of the ascending pharyngeal artery. The stylopharyngeus is the only muscle of the pharynx innervated by the glossopharyngeal nerve (CN IX) (all others being instead innervated by the vagus nerve (CN X)) by special visceral motor neurons with their cell bodies in the rostral part of the nucleus ambiguus. Some of its fibers are lost in the superior and middle constrictor muscles, some merge with the lateral glossoepiglottic fold, while still others join with those of the palatopharyngeus muscle to insert onto the posterior border of the thyroid cartilage. It is the only muscle of the pharynx not to originate in the pharyngeal wall. It arises from (the medial side of the base of) the temporal styloid process. It passes inferior-ward along the side of the pharynx between the superior pharyngeal constrictor (situated deep to the stylopharyngeus) and the middle pharyngeal constrictor (situated superficial to the stylopharyngeus), before spreads out beneath the mucous membrane. It is cylindrical superiorly, and flattened inferiorly. The stylopharyngeus is a long, slender, tapered pharyngeal muscle. It acts to elevate the larynx and pharynx, and dilate the pharynx, thus facilitating swallowing. It is innervated by the glossopharyngeal nerve (cranial nerve IX). Some of its fibres insert onto the thyroid cartilage, while others end by intermingling with proximal structures. It originates from the temporal styloid process. The muscles of the pharynx are supplied by the pharyngeal plexus, a network of nerves from pharyngeal branches of the vagus and glossopharyngeal nerves.The stylopharyngeus muscle is a muscle in the head. Most lymph drains back to the retropharyngeal nodes. Veins of the same name drain either into the pterygoid venous plexus or directly into the internal jugular vein.
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