MYONET - Atlas Musculature Orofacial System

Atlas Musculature: Deglutition Action

Erhard Thiele     025e Atlas Musculature Inventory       MYONET.TOTAL PROGR CONTENTS  

I.3.5 The Physiological Act of Deglutition

 Citation: Rauber-Kopsch

(The following text is a re-translation from German)

In the deglutition act the bolus of foodstuff prepared in the mouth is moved through the gullet of the fauces, the cavity of the Pharynx and the oesophagus into the stomach. Though the swallowing can be started voluntarily but continues as a consistent reflex action which can, then, not be impeded voluntarily. From didactic reasons the deglutition act can be split up into the (voluntarily influenced) preparation phase, further the genuine act of deglutition proceeding rapidly in the mouth- throat-region and in the transportation phase through the oesophagus. In the preparation phase, after crushing and salivation of the food the oral diaphragm gets contracted voluntarily, the bolus being pressed against the soft palate. The thus created stimulation of the receptors of the palatal mucosa is triggering the decisive swallowing process. During this decisive swallowing process two fast moving procedures are being synchronised, the reflectory safeguarding of the airways and the transportation of the bolus through the fauces - the airways (nose, larynx) are endangered during the transport of the bolus as in the pharynx the path of food and air are crossing.

The reflex protection of the airways encloses the closure of the Pars nasalis pharyngis and the laryngeal inlet. The Pars nasalis is sealed off from the Pars oralis pharyngis by the Mm. tensor und levator veli palatini lifting and tensioning the velum pressing it against the back wall of the pharynx which in this very level forms the Passavant's bar, a bulge, in a localised contraction of the upper Constrictor pharyngis and M. palatopharyngeus passing in front of it When the Velum suffers a paralysis, for example secondary to diphtheria, foodstuff is getting into the nasal cavity. The Larynx inlet is closed by two mechanisms: by lifting the larynx and through a fat tissue mechanism. The Larynx gets lifted by the help of the Mm. mylohyoidei, Mm. digastrici and the Mm. thyrohyoidei simultaneously lifting the Os hyoides visibly; this moves the Laryngeal inlet nearer to the Epiglottis and maintains a complete closure with the help of the Mm. aryepiglottici. Their fat tissue mechanism comprises: when during the passing back of the tongue ground a fat pad lying in front and besides the Epiglottis in the connective tissue is pressing on the Epiglottis thus nearing it to the Larynx inlet creating a further (incomplete) closure. For the instance of the deglutition act generally a consensual closure of the Glottis and asphyxia is maintained. The voluntary irritation of the mechanisms protecting the upper and lower airway (for example to try to speak when swallowing) leads to choking.

The transportation of the bolus trough the fauces is equally safeguarded through several mechanisms. The tongue urges the bolus like a plunger into the Isthmus faucium pulled from the Mm. styloglossus and hyoglossus while the intrinsic muscles of the tongue billow the tongue base against the isthmus. The musculature of the isthmus, the Mm. palatoglossi, transversus linguae and palatopharyngei reflectorically squeeze a bite off the food and lift it into the fauces. It is pushed into the pharynx. The pharynx, its lumen habitually forming a transverse slit, distends with the lifting of the larynx up and forward. The bolus glides mainly through the Recessus piriformis (chiefly on the chewing side) partially also across the Epiglottis. With an abridging of the Constrictor inferior a dorsal sinus of the retral pharynx wall is formed, which, lifted through the contraction of the Mm. palatopharyngei, models a sack which takes up the bolus. The contraction of the pharyngeal constrictors leads the bolus into the Oesophagus. The transportation phase through the Oesophagus (for example for liquids) comes about solely through a rapid strong contraction of the oral diaphragm and superior contractors happening in upright position as a squirting push or (for solid food) by continuous contraction waves - peristalsis - of the Oesophagus. [126, p.219]

As the above description refers to the passage of the foodstuff from the retral rim of the oral cavity to the stomach, in the follow shall be added the section being of quite some importance for the Myofunctional Therapy in the Orofacial System from the rostral part of the Cavum oris to its back rim. The description is cited from the paper: Thiele, E. (see next page).: The Action Chain of the Swallow Reflex: Activities and Assignments, Page 369 f.f. in: Hanson, Marvin, L.: Orofacial Myology international perspectives (2.Edition) by: Charles C. Thomas-Publishers Ltd., Springfield, Illinois 2003. 62704 ISBN 0-398-07359-7

(See also Catalogue of Exercises‚exc214e-swallowmechanism.doc’)