New!

January 8th, 2022| Topic: RaMbLeS | 0

Well, what about that? We humans have a body part that’s never been seen before! Whodda thunk it?

So claim anatomy researchers from the University of Basel, Switzerland, in “The Human Masseter Muscle Revisited: First Description of Its Coronoid Part,” published in the Annals of Anatomy last month.

As one correspondent reported, it’s a jaw-dropping discovery. Literally. Because the masseter muscle is a muscle in our lower jaws essential for chewing. It’s the hunk of tissue we feel on the side of our faces when we clench our teeth—that clenching is caused by the contraction of the masseter. It’s presence on our faces also gives it special significance for facial aesthetics and contouring.

We already knew that the masseter had a deep layer and superficial layer. There is, now, apparently a third layer to this muscle.

Suspicions about this new layer had existed since the days of Gray’s Anatomy (the classic text, not the TV show), but Henry Gray in 1858 was only referencing an older observation made in 1784 in the German textbook, Grundriss der Physiologie für Vorlesungen (“Outline of Physiology for Lectures”). But it was all rather controversial and in dispute.

So, say the authors of our current paper:

In order to clarify the structure of the masseter and the resulting inconsistency in nomenclature, we performed anatomical dissections and methylmethacrylate embedding of formaldehyde-fixed cadavers, and supplemented this by computer tomography (CT) examinations of fresh cadavers and magnetic resonance (MR) imaging of a live subject.”

Twelve human heads from corpses preserved in formaldehyde served as the “subjects” of this study.

“As a result, we describe and show here for the first time a distinct portion of the human masseter muscle, which we suggest should be called the coronoid part (suggested Latin name: M. masseter, pars coronoidea).”

According to lead author Dr. Szilvia Mezey of Basel’s Department of Biomedicine:

This part of the muscle likely stabilizes the lower jaw and seems to be the only part that can pull the jaw backward, towards the ear.”

Added senior author Prof. Jens Christoph Tür of University Center for Dental Medicine Basel:

It’s as if a new animal species had been found.”

Yup, this is a major find, at least to demonstrate the depth of our ignorance, even of matters pertaining to human anatomy and body parts we all bear and carry.

But there is Someone who knows it all! Because he is God!

Before the mountains, [before] they were born,
and [before] You delivered the earth and the world,
and from forever unto forever, You [were] God.
Psalm 90:2

He is the Creator of everything, visible and invisible.

By the word of Yahweh the heavens, they were made,
and by the breath of His mouth all their host.
Psalm 33:6

… including humanity. And even the humble M. masseter, pars coronoidea.

What a God!

How Your works have abounded, Yahweh!
All of them in wisdom You have made—the earth is full of Your possessions:
here is the sea, great and wide in reach;
there are swarms without number, animals, small with great. …
All of them, they wait for You to give their sustenance at its time.
You give to them, they gather; You open Your hand, they are satiated with good. …
You take away their spirit, they expire and to their dust they return.
You send forth Your Spirit, they are created. …
Let the glory of Yahweh be forever; Let Yahweh rejoice in His works.
Psalm 104:24–25, 27–31

And he does. Even in the M. masseter, pars coronoidea!

SOURCES:
Jerusalem Post; Annals of Anatomy