The newly found muscle layer runs from the back of the cheekbone to the anterior muscular procedure of the lower jaw. (S= superficial layer, D= deep layer, C= coronoid layer).” This deep section of the masseter muscle is clearly distinguishable from the two other layers in terms of its course and function,” describes Mezey. The plan of the muscle fibers, she states, recommends that this layer is included in the stabilization of the lower jaw.
The physiological study was based on comprehensive assessment of formalin-fixed jaw musculature, computer tomographic scans and the analysis of stained tissue areas from departed individuals who had actually donated their bodies to science. This was in addition to MRI data from a living individual.
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” This deep section of the masseter muscle is clearly appreciable from the two other layers in regards to its course and function,” discusses Mezey. The plan of the muscle fibers, she states, suggests that this layer is associated with the stabilization of the lower jaw. It also appears to be the only part of the masseter that can pull the lower jaw backwards– that is, towards the ear.
An appearance at historical anatomy studies and textbooks exposes that the structure of the masseter muscle has already raised questions in the past. In a previous edition of Grays Anatomy, from the year 1995, the editors likewise explain the masseter muscle as having 3 layers, although the pointed out research studies were based on the jaw musculature of other species and partly contradicted one another.
Other private research studies from the early 2000s also reported three layers, however they divided the shallow section of the masseter into 2 layers and agreed with basic operate in their description of the much deeper area.
” In view of these inconsistent descriptions, we wished to take a look at the structure of the masseter muscle again adequately,” says Türp. “Although its usually presumed that anatomical research in the last 100 years has actually left no stone unturned, our finding is a bit like zoologists finding a brand-new species of vertebrate.”
Reference: “The human masseter muscle revisited: First description of its coronoid part” by Szilvia E. Mezey, Magdalena Müller-Gerbl, Mireille Toranelli and Jens Christoph Türp, 2 December 2021, Annals of Anatomy– Anatomischer Anzeiger.DOI: 10.1016/ j.aanat.2021.151879.
The newly discovered muscle layer runs from the back of the cheekbone to the anterior muscular process of the lower jaw. (S= shallow layer, D= deep layer, C= coronoid layer).
Human anatomy still has a few surprises in store for us: researchers at the University of Basel have actually found a previously overlooked area of our jaw muscles and explained this layer in detail for the very first time.
The masseter muscle is the most prominent of the jaw muscles. If you position your fingers on the back of your cheeks and press your teeth together, youll feel the muscle tighten. Anatomy textbooks generally describe the masseter as consisting of one superficial and one deep part.
Now, scientists led by Dr. Szilvia Mezey from the Department of Biomedicine at the University of Basel and Professor Jens Christoph Türp from the University Center for Dental Medicine Basel (UZB) have explained the structure of the masseter muscle as consisting of an extra 3rd, even much deeper layer. In the scientific journal Annals of Anatomy, they propose that this layer be offered the name Musculus masseter pars coronidea– to put it simply, the coronoid section of the masseter– due to the fact that the recently described layer of muscle is attached to the muscular (or “coronoid”) procedure of the lower jaw.
