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Here’s an exciting discovery for the top of the year.

A team of researchers has recently discovered a new part in the human body, a deep third layer of muscle in the masseter muscle, which is critical for chewing. 

Most modern anatomy textbooks describe only two layers of the masseter, stating that the muscle has only two layers, one deep and one superficial layer. But a study published in the journal Annals of Anatomy describes the third layer of the muscle in detail. 

The team that made the discovery was led by senior lecturer 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. 

The researchers dissected 12 human cadaver heads that were preserved in formaldehyde, and took CT scans of 16 fresh cadavers, and also reviewed an MRI scan of a living subject and identified an “anatomically distinct” third layer of the muscle as a result of these examinations, according to the report. 

“This deep section of the masseter muscle is clearly distinguishable from the two other layers in terms of its course and function,” Mezey, author of the research, said in a statement. “Although it’s generally assumed that anatomical research in the last 100 years has left no stone unturned, our finding is a bit like zoologists discovering a new species of vertebrate,” adds senior author Türp.

In their report, the team said based on the muscle fibers’ arrangement, the muscle layer likely helps stabilize the lower jaw by “elevating and retracting” the coronoid process. In addition, Mezey explained that the newfound muscle layer is the only part of the masseter that can pull the jawbone backward.

The lead researchers proposed the layer be named “Musculus masseter pars coronidea” or the coronoid section of the masseter because the newfound layer is connected to a small triangular section of the lower jaw called the coronoid process. The discovery could be significant in a clinical context because knowing about the muscle layer could help doctors better perform surgeries in that region of the jaw and better treat conditions involving the joint that connects the jawbone to the skull, the researchers noted.

Although it may seem a little crazy to think that scientists are still discovering new organs and muscles, it’s not unusually rare. Take, for example, the team that discovered an extra set of salivary glands right inside our heads.

It seems we will never get to the end of how uniquely, fearfully, and wonderfully we have been designed by a masterful Creator!