MYONET - Atlas Musculature Orofacial System

Atlas Musculature: Specialities,I,1,2,3,4

Erhard Thiele     013e Atlas Musculature Inventory       MYONET.TOTAL PROGR CONTENTS  

1.1.3 Analysis of the muscular Specialities of the Muscles of Area I

Orofacial System

 

Abb.17a/b:   Setting of the  Muscle Areas of the Synchronically Connected Muscle Areas of the Orbicularis Oris from a Functional  View (Rings: peripheral, medial, central and slices, sagittal)

I/1. (M. nasalis) A portion of the  pars alaris originating from the alveolar bone of the lateral upper incisor radiates into the upper lip pulling it in sideways centripetal direction. The Orbicularis (4) lies upon it accentuating the centripetal effect of it. > flattening the Vestibulum, stress on the upper maxillary incisors, uni- or bilaterally explicitly the lateral.

I/2. (M. depressor septi) Also viewed as part of the Orbicularis (4) and may be additionally parted into a M. apicis nasi (nose root muscle) leading to the nose tip widening the frontal part of the nostril. It obeys, in a somewhat altered way, the above said, accentuating the pressure on the medial upper incisors.

 I/3. (M. levator labii superioris et alae nasi) The lateral fascicle passes on into the lateral part of the upper lip and shows a intertwining with the  Levator labii superioris (8) and the Orbicularis (4). It can lift and extrovert the upper lip which would weaken the centripetal power here.

 I/4. (M. Orbicularis oris) The Orbicularis is the muscular basis of the lips. It forms a function set with the "wheel spokes". Most remarkable is its originating from the intermediate tendon passing vertically to the mouth slit effecting that no true ring muscle is formed but rather two bows. These intermediate tendons also serve as the fixing point for the "spokes" running towards the mouth angle (see above). All those muscles originating at the incisor alveolar bone are also called Musculi incisivi labii superioris/inferioris.               ---------             For the Orbicularis itself anatomically three main bundles can be differentiated (in contrary to the before described categorisation into functionally coupled areas - see picture 17a, b.) The Pars marginalis is situated in the region of the Prolabium and bends with its fibres in an uncinate way outside. The peripheral part of the three bundles is named Pars labialis being the main component. The third part is the Rectus system with a radial orientation. Here upon are following the wheel spoke fibres making this system similar to that we will, later on,  meet in the tongue - intrinsic muscles and from outside, raying in, the fibres of the Depressor septi from the nasal septum, fibres of the Buccinator, from the levator and depressor of the lips running till the median line. These, same as those from the Zygomaticus (6) are directed in a slightly oblique way by intertwining and crossing from upper and lower lip at the mouth corner creating a nodule. At this site the Modiolus is easily palpable and partially to be made out through the covering skin. In the common "wheel spoke" picture it represents, as described above, the wheel hub, or, more precisely, one half of half the wheel in the one side of the face. Through a specific coordination of the muscle tone of the spokes the Modiolus can be fixed in any position desired around the mouth angle region. This is of some major importance for our belongings once in respect of an excess exertion of power and more over as a location stimulating to be gnawed on. In respect of the power exertion and inward pressing strength Gray describes fibres running in a rectangular direction from out to inside, from the deep skin surface through the lip prominence to the Membrana mucosa. The deep fibres are further pressing the lips against the front teeth while those lying more to the surface are pulling the lips nearer to each other and protruding them. The respective special physiology has already been discussed in the paragraph with the "wheel spoke comparison".