![]() While type B, an accessory bundle ran inferomedially and inserted into the pharyngeal raphe. In type A, an accessory bundle ran longitudinally and may help the STP performing pharyngeal shortening. An accessory bundle was thick as if it compensates for the thin STP. The STP with an accessory bundle had thinner than without an accessory bundle, so it may reduce its pharyngeal shortening function. Accessory bundle was classified two type according to its running pattern. According to the present findings, the STP had accessory bundles in 18.2% (8/44) of cases. This study observed the origin and variations, therein, of the STP with the SC muscle and considered its function based on its morphology. Some variations in their topography along with additional bundles of STP fibers were classified according to origin and insertion site.Īll photographs and diagrams in this article are structures viewed from the right side of the pharynx. The STP and three constrictor muscles were observed. The neurovascular bundle, innervating the pharyngeal muscles, was removed from the posterior side of the pharynx to allow for a clear observation of the muscular morphology of pharyngeal muscles. The pharyngeal musculature was observed through careful dissection using the aid of a surgical microscope (OPMI-FC Carl Zeiss, Oberkochen, Germany). The specimens included an origin of the STP with the styloid process. The pharynx was separated from the skull base, and the cervical vertebrae in the posterior wall was removed to allow for a clear observation of the pharyngeal posterior wall. The aims of this study were to clarify the topography and variations of both STP and SC muscles, to validate anatomical relationship between STP and SC, and to examine what role they play in the pharyngeal movement.įorty-four specimens (22 right and 22 left sides) from 22 embalmed Korean adult cadavers (13 males, 9 females age range, 46–89 years mean age, 69.2 years) were used in this study. ![]() However, more detailed study is needed to understand the topographic characteristics and anatomical variations of the SC muscle. Moreover, some fibers of the SC muscle are directly attached to the velum, and thus, might assist in retraction thereof. Previous studies have considered the functions of the SC muscle from the perspective of its anatomical morphology: it is attached to the buccinator muscle, which enables a smooth transition from the lingual stage to the pharyngeal stage during ingestion. Their interaction can only be elucidated by observing their topographic relationship on both the inner and outer surfaces of the pharynx. However, the two muscles do not work independently. It is well known that the STP is critically involved in shortening the pharynx and elevating the larynx while the SC muscle plays a critical role as a sphincter muscle. Thus, there is a particularly close relationship between the STP and the SC muscle. As an exception, the STP arises from the outside of the pharynx (i.e., the styloid process) and penetrates the posterior wall (i.e., the pharyngeal constrictor muscles) into the pharynx. ![]() Īlmost all muscles of the pharynx originate and insert into the internal surface of the pharynx. Therefore, a complete understanding of the pharyngeal function requires a detailed knowledge on the morphology of each muscle and relationships between them. These muscles are not simple structures and do not work individually they move and function together in sync. It is well known that three external circular muscles (superior constrictor, middle constrictor, inferior constrictor ) act as the sphincter, and three internal longitudinal muscles (the stylopharyngeus, palatopharyngeus, and salpingopharyngeus) elevate the pharynx. The pharynx, a tube-like structure, is a part of the digestive system and is composed of six muscles.
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