MYONET - Atlas Musculature Orofacial System

Atlas Musculature: VII

 Erhard Thiele     032e Atlas Musculature Inventory       MYONET.TOTAL PROGR CONTENTS  

 

1.6.2 Discussion of the Physiology and Muscular Specialities and faulty actions

of Area VII – Masticatory Muscles –

As the orofacial system is overlapping with a multitude of neighbouring areas through morphology and function we, here too, are reaching into the stomatognathic system which  comprises the upper and lower jaw bone, the TM joints and the respective musculature . We are drawn into this area when following the reflexes of the orofacial system. These might be  briefly alluded

Mandibular resting position, adductor (mastication) function, mandibular protrusion in the sucking reflex, mis-habits like chewing on Lips, cheek or tongue, faulty phonation and articulation, head posture, oral posture; especially mentioned the OMP (Open Mouth Posture). If tongue and lip posture are maladjusted consequently the whole stomatognathic apparatus and, moreover, the craniocervical system is affected - for the following reason: The mandible is kept in its hovering position not only through the musculature mentioned on the next page but moreover and additionally through the pneumatic conditions within the articular capsule as  well as in the oral cavity (see also publication on the website mentioned further down:"

26012011. On the  pneumatic conditions within the Stomatognathic System. (Claaudia Scholz, Erhard Thiele; Kiel/Germany). If the Corpus mandibulae would only be held in situ muscularly this would mean a stress generating muscular permanent load. It is this a substantial reason for an early surgical correction of clefts in the lip, jaw and velum region.

Furthermore a patient will become a case for the Myofunctional Therapy when he is exhibiting changes of the temporomandibular joint (TMJ). We are confronted with these cases on one side which have fractures of the joint processes of the Ramus mandibulae) or, if a damage appeared on the joint surfaces or on the Discus Intercondylaris. This might very well happen either through dysfunctions like grinding or pressing or through inflammatory changes as for example in cases of JIA (Juvenile Idopathic Arthritis). Here therapy will practically not get along without the help of the Myofunctional Therapy. For the treatment of adults a possibility might perhaps be a splint having been manufactured precisely for the respective masticatory system.

(See: paper in  ZMK from January/February 2009 by Dr. Margit Weiss, Möglichkeiten der Schnarchtherapie durch den Zahnarzt, discussed in: www.ccmf.de/news/ccmfnewstitel.htm  in the article: "21042011:Cooperation  with the 'Deutsches Zentrum für Kinder-. Und Jugendrheumatologie, Sozialpädiatrisches Zentrum in Garmisch-Partenkirchen/Germany, Leiter Pd. Dr. J.-P. Haas"

"21042011: Kooperation  mit dem Deutschen Zentrum für Kinder-. Und Jugendrheumatologie, Sozialpädiatrisches Zentrum in Garmisch-Partenkirchen". This does not apply to dentitions being in the development phase (dentition change) .  This, just to emphasize, is not true for dentitions in a phase of development (dentition change). here a splint should be seen as contraindicated as it is blocking the jaw and denture development. More about this is also published on the mentioned website under the date  22092010:
"A new publication  on the subject "Rheumakids" in connection with MFT-Treatment has reached our publication staff:: The MFT-Concept in the Therapy of „Rheumakids“ Claudia Scholz, E. Thiele, Kiel, 20.09.2010."

Commonly the Masseter is seen as a pars-pro-toto for the masticatory muscles. Although we do not get along solely with it as we further need the  forward push, the back pull (pro- and retrusion) and the sideshift (translatio). The actual chewing musculature generally consists of bilaterally four muscle tracks which are arranged around  /in front of the ears, have their origin at the skull bones (Neurocranium) and their insertion  at the lower jaw bone. Developmentally the masticatory muscles stem from the first gill arch. Their motor nerve is the N. Trigeminus. The nerval-motor control is managed in a feedback loop with its centre (masticatory centre) in the central nerve system. Up to this point the signals about posture and load of the parodontium (of teeth and jaw bones) are transmitted, and from these informations the regulation of the chewing muscle tonicity tuned. Interesting for us as we will have to explain why the tongue or a thumb are able to bend up the jaw arches. We surely will have to assume that this sort of loop is also integrated into our "bulb-shell" (see  Abb. 16 page 10) to balance the inside against the outside. By this we are able to explain the interruption of the feedback loop for example by a thumb and the consequent deformations and dysbalance. [Dysbalances resulting from the fact that loop control will conclude from the incoming neural information that the physiological state is existing, which, though, is just simulated through some dysfunction.]

 

VII/1. (M. masseter)
This muscle (inner and outer part) lifts the mandibula in a centred manner; it is ascribed no participation in the grinding movement. It is primarily responsible for the function of biting-off by the front teeth and the mashing in the lateral regions. It is assigned a pressure output of 500 grams. We should follow the question whether we might state characteristics about dys- (hyper or hypo)-functions by its evaluation. For the lifting up of the mandible to perform a mouth closure only a fraction of its maximal power is necessary; furthermore the mouth closure is maintained additionally through the inner negative air pressure. The outer (lateral) part of the muscles a slight forward trend in the motion may be ascribed. Muscle actions become visible and palpable through a swelling in the cheek region rostral to the jaw angle. And here the deformations of the skeleton from hyperactivity will become visible when the mandibular angle is bent outside, mostly bilaterally, thus creating a square or upside down triangular face form, further the characteristical myogeloses can, then, be palpated (q.v. MASSETER EXERCISE).

 

VII/2. (M. temporalis)

Sturdier then the masseter seems the Temporalis lying broadly upon the temple like a fan. This justly suggests that it may act in parts and resultantly pull in divergent directions as the small sketch indicates. Its actions, too, are accompanied by a visible 'swelling' clearly observable above and in front of the ears (as equally those myogeloses). Functionally this is the 'biting' muscle. It generates  great power during the process of biting-off as well with the jaw wide apart as when the dental arches are in occlusion but is loosing power in the protrusive position. Its threefold structure enables it to manoeuvre  the joint head during grinding movements. (Under hyperfunction characteristical temple aching will occur.)
 
 
 
VII/3. (M. pterygoideus medialis)
The two above described  muscles representing the two bigger and more outwardly situated ones, the Medialis is sited  on the oral side of the manibular bone running, as shown in the sketch Abb. 30 in a slanted direction not only in the vertical axis from top-front to bottom-back towards the inner plain of the jaw angle but, as well, from inside to outside. Together with the Masseter it forms an elevation sling. Separately it effectuates  bilaterally a mandibula protrusion, unilaterally a singelesided panning forward of the respective joint head during grinding movements. Thus it dominates in the sucking position, some sucking positions and nibble posture. Due to its size it may easily be overloaded with the respective consequences.