MYONET - Atlas Musculature Orofacial System

Atlas Musculature: Specialities 3,1,2,3

Erhard Thiele     023e Atlas Musculature Inventory       MYONET.TPTAL PROGR CONTENTS  

1.3.2 Discussion of the Physiology

            of the Muscles of Area III

–        Diaphragma oris and Velum palatinum –

The oral diaphragm musculature is involved in all muscular functions of the orofacial system, for speaking, chewing and swallowing.  J. W. Rohen comments:

"For the functioning mechanism of the chewing apparatus also the mouth floor muscles and the long muscle loops at the neck (rectus group, hyoid musculature) are involved. The muscles are of different origin and primarily influence the position of the larynx. They form long elastic loops for the elastic stabilisation of the cervical viscera in connection with the chewing apparatus. When comprehending which meaning the oral cavity of a human has gained for the speech apparatus the near functional connection of this muscle group to the chewing apparatus gets understandable." And he goes on: “At the hyoid bone first the mouth floor muscles suprahyal muscles) are fixed, second the long muscles of the neck viscera (infrahyal muscles) and, third the deep muscles of the second branchial arch. All three groups are connected to one functional system which stands in a close connection to the chewing apparatus. The mouth floor muscles are mostly filling the frame formed by the mandible. Longitudinal and transversal muscles are distinguished arranged in layers on top of one another."[136, S. 245 f.]  

Within these layers follows beneath the tongue the Geniohyoideus, then the transversal running Mylohyoideus with its tendineous Raphe in the median line - the original mouth floor (Diaphragma oris) - which downwards continues fibrous forming here gates for the pathways. This is followed, again in longitudinal direction, the Digastricus with its frontal venter. When the mouth floor muscles are relaxed the tongue sinks into nit like in a hammock thus enlarging the volume of the oral cavity which is essential for the ingestion and speech. The musculature can tense gradually thus lifting the tongue body up like on a lifting stage. In synergism we get a strong abutment during tongue movements through the tensed musculature as, for example, during deglutition.


1.3.3 Discourse About the Muscular Specialities of the Muscles of Area III

III/1. (M. geniohyoideus)

Frequently a fibrous connection of the muscle bundles of both sides exits or, as well, the fibres are switching to the opposite side.

III/2. (M. mylohyoideus)

Its shape has a great variation range. It can show additional longitudinal fibres at the rim, form one plane or a front and back plane, may show gaps or be completely missing and substituted through an enlarged frontal digastric venter or be only fused with it. These equally for the other areas described muscular specialities may certainly often help explain why a certain function is only incompletely performed and only by aimed muscle function training possibly taken over by other muscle tracks.

III/3. (M. digastricus)

It is the most variant muscle. The anterior venter may be missing, both venters doubled, the posterior show an additional muscle - the Occipitohyoideus - the anterior venters may be enlarged in a sort of Diaphragma, may join up in the median line and exchange fibres.

From its construction the Platysma (I/13) also has a function as a mouth floor stabilisation.