Anatomical Significance of the Spatial Distribution of the Palatopharyngeus With Regard to Velopharyngeal Closure

Abstract

Objective:

Coordination of the various soft palate and pharyngeal muscles should be considered while evaluating velopharyngeal closure. However, it remains unclear whether different muscle bundles have specific functions during velopharyngeal closure. We macroscopically and microscopically examined these muscles in detail and particularly clarified the morphology of the palatopharyngeus (PP) in velopharyngeal closure.

Design:

Forty halves of 21 heads from Japanese cadavers (average: 83.9 years) were used for analysis; 37 halves of 19 heads were macroscopically examined and 3 halves of 2 heads were histologically examined.

Results:

The PP consisted of muscle bundles originating from the superior and inferior surfaces of the palatine aponeurosis. The most superior part of the superior constrictor (SC) and most lateral part of PP on the palatine aponeurosis initially ran in parallel and subsequently, in superoposterior and inferoposterior directions, respectively. The PP appeared as a single continuous sheet that was radially spread as a whole. Its medial margins, located superior and inferior to the aponeurosis, formed a fold that established the palatopharyngeal arch. The stylopharyngeus (StP) adjoined the base of this arch.

Conclusions:

Since PP consisted of muscle bundles running in various directions, various functions of these bundles should be considered during velopharyngeal closure. The PP can function as a sphincter with SC and as an elevator with StP. In addition, PP forms the medial protrusion in collaboration with StP and SC. Thus, PP plays an important role in velopharyngeal closure with the coordination of various muscles.