ヒト咽頭挙筋群の起始・走行ならびに停止に関する肉眼解剖学的研究

Using 50 cadavers, the pharyngeal longitudinal muscles, the palatopharyngeus, salpingopharyngeus and stylopharyngeus, were bilaterally dissected out as the full length of muscles. Using another 5 cadavers, the arrangement of muscles in the soft palate and around the epiglottic vallecula (EV) and the piriform fossa (PF) was histologically observed. The palatopharyngeus formed the base of the soft palate. The muscle was divided into superficial and deep portions. The superficial portion penetrated the soft palate by the levator veli palatini muscle (LVP) to be subdivided into four, A1 to A4, origins of muscle. The four origins gathered to form the palatopharyngeal arch and descended to EV and PF. A1 arose from the median plane between the aponeurosis palatini (AP) and LVP, and A2 arose from AP, both of which ran caudally on the oral side of LVP. A3 arose from AP with the intervention of connective tissue on the nasal side of LVP, and A4 arose from the lateral margin of the uvula posterior to LVP. The deep portion arose from AP on the nasal side of A1 and A2, and ran on the oral side of LVP and then surrounded the pharyngeal isthmus to finally reach the pharyngeal raphe. The salpingopharyngeus arose from the Eustachian tube cartilage and immediately joined the superficial portion of the palatopharyngeus, from which finding the salpingopharyngeus was regarded as one of the origins of the superficial portion. The stylopharyngeus arose from the styloid process and entered the submucous layer of the pharynx to join the superficial portion of the palatopharyngeus. The muscle bundle formed by the two muscles had four insertions. Insertion 1, derived from the stylopharyngeus, descended to reach submucous layers of EV. Insertion 2, derived from the stylopharyngeus and palatopharyngeus, descended to attach to the posterior border of the thyroid cartilage. Insertions 3 and 4, derived from the palatopharyngeus, descended inside the pharyngeal constrictors to reach the submucous layer of the posterior pharyngeal wall and the pharyngeal raphe, respectively, in PF. The insertions of the stylopharyngeus and palatopharyngeus were arranged to surround EV and PF, from which finding the two muscles were suggested to have the action of moving the mucous membranes of EV and PF to help the passage of food, in addition to the sphincter action of the pharyngeal isthmus, the depression of the soft palate, and the elevation of the pharynx.