152 Joint of the Jaw. 



Tuberculum articulare Arcus zygomaticus 



Discus articularis 

 Fossa mandibularis 



-< Ramus mandibulae 



^^m 



articularis 

 ; Meatus acusticus 

 ,' externus 



Processus mastoideus 



^^^ 



204. Jaw joint of right side, arliculatio mandibularis, 



from without. 



(The arcus zygomaticus and the processus condyloideus mandibulae have been partially removal: 

 the parts have been somewhat separated from one another.) 



By means of the articulatio mandibularis (joint of the jaw) (0. T. temporo- maxil- 

 lary articulation) (see also Figs. 205 207) the lower jaw is movably connected with the rest 

 of the skull. The capitulum of the processus condyloideus mandibulae on each side rests on 

 the posterior slope of the tuberculum articulare in the fossa mandibularis ossis temporalis. 

 The facies articularis extends into the fossa mandibularis not quite as far as the fissura petro- 

 tympanica where it is for the most part covered by connective tissue and only in its most 

 anterior portion covered with cartilage; in front it goes over upon the tuberculum articulare 

 which is covered with cartilage and does not end until its anterior slope is reached. The car- 

 tilaginous covering consists of fibrocariilage. Between the processus condyloideus on the one 

 side and the fossa mandibularis and tuberculum articulare on the other is inserted a connective 

 tissue disc, discus articularis (0. T. interarticular fibrocartilage) , which is thinner in the 

 middle, thicker in front and behind and about of the shape of a biconcave tranversely placed 

 plate. The capsula articularis (0. T. capsular ligament) is loose and is stretched from the 

 circumference of the facies articularis of the fossa mandibularis and of the tuberculum articulare 

 to the upper margin of the discus articularis, as well as from the lower border of the latter to 

 the collum (neck) of the processus condyloideus mandibulae. In this way two joint cavities, 

 completely separated from one another, are formed, an upper and a lower, which are separated 

 from one another by the articular disc. 



