For the first time, scientists have pinpointed the muscle that aids in chewing food. This group of muscles is present in the masseter – the part of the skull that helps move the jaw and is crucial to help chew food.
Until now, most anatomy books discussed only two prominent layers of muscles present in the masseter: one that lays deep and the other one is superficial. However, according to a new study published in the journal Annals of Anatomy, a third deep yet inconsistent muscle layer was recorded.
This study analysed over twelve formaldehyde preserved human cadaver heads and over sixteen fresh cadavers using CT and MRI scans. During this thorough study, an ‘anatomically’ unique third layer was identified in the masseter muscle that stretches from the zygomatic process to the coronoid process. This means this particular muscle layer is present between the cheekbones and the lower jawbone. It differs from the other muscle layers in their functionality and course.
As per the researchers, this muscle layer helps stabilise the lower jaw by causing elevation and retraction of the coronoid process. Also, the scientists noted that this newly discovered muscle layer is the sole section of the masseter that aids in pulling the jawbone in the backward direction. Therefore, this new body part has been named the ‘Musculus masseter pars coronidea’ or the ‘coronoid part of the masseter’.
With the discovery of this new body part, doctors will now be more aware during the treatment and surgeries, especially those involving the jaw regions and the joint between the skull and the jawbone.