98 - Anatomical Variation in the Site of Origin of the Human Levator Veli Palatini Muscle: Attempting to Clarify Three Centuries of Ambiguity

Poster Board Number: 98
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Co-authors:

hanin Bachir - Hackensack Meridian School of Medicine; taegn Denning - Hackensack Meridian School of Medicine; Tuan-Dat Nguyen - Hackensack Meridian School of Medicine; Michelle Titunick - Hackensack Meridian School of Medicine; Samuel Márquez - SUNY Downstate Health Sciences University

Abstract Body : The levator veli palatini (LVP) is a crucial soft palate muscle for speech, swallowing, and respiration. Yet its precise origin remains unclear among anatomists and clinicians. Conflicting reports dating back three centuries have placed its origin in several locations. Some have claimed that LVP fibers originate close to the osseous Eustachian tube orifice (OEO) while others have proposed an origin from the quadrate surface of the petrous temporal bone. We dissected ten mid-sagittally sectioned heads at the Hackensack Meridian School of Medicine and one from the SUNY Downstate Health Sciences University. Each half-head was sectioned obliquely along the LVP. It was discovered that the LVP took origin either immediately around the OEO rim or from the posterior wall of the osseous Eustachian tube itself. In some individuals, additional muscular fibers attach immediately posterior to the OEO on the thick fibrous tissue layer covering the petrous temporal bone. Much of the area surrounding the proximal LVP posteriorly up to the carotid sheath was occupied by this thick fascia that appeared to take root on the portions of temporal bone between the OEO and the carotid foramen. Additional fibers of the levator veli palatini took attachment from the carotid sheath itself on more distal portions of the muscle. These accessory fibers could impact the function of the levator by altering potentially both its directional vector of contraction and mechanical advantage when moving the soft palate. Understanding of such basic human anatomy, especially for a muscle as important as the LVP, informs not only skull base surgery and radiology, but also research on the evolution of human speech. Future work should analyze the relationship between skeletal and soft tissue anatomical variation in the area to better reconstruct palatal musculature among fossil hominins.