THE MOUT1 



i 129 



hyoid bone. In either half there are two 1 sets of muscles, extrinsic and intrinsic; 

 the former have their origins outside the tongue, the latter are contained entirely 

 within it. 

 The extrinsic muscles (Fig. 1019) are: 



Genioglossus. Chondroglossus. 



Hyoglossus. Styloglossus. 



Glossopalatinus. 1 



FIG. 1019. Extrinsic muscles of the tongue. Left side. 



The Genioglossus (Geniohyoglossus) is a flat triangular muscle close to and par- 

 allel with the median plane, its apex corresponding with its point of origin from the 

 mandible, its base with its insertion into the tongue and hyoid bone. It arises 

 by a short tendon from the superior mental spine on the inner surface of the sym- 

 physis menti, immediately above the Geniohyoideus, and from this point spreads 

 out in a fan-like form. The inferior fibers extend downward, to be attached by a 

 thin aponeurosis to the upper part of the body of the hyoid bone, a few passing 

 between the Hyoglossus and Chondroglossus to blend with the Constrictores 

 pharyngis; the middle fibers pass backward, and the superior ones upward and for- 

 ward, to enter the whole length of the under surface of the tongue, from the root 

 to the apex. The muscles of opposite sides are separated at their insertions by the 

 median fibrous septum of the tongue; in front, they are more or less blended owing 

 to the decussation of fasciculi in the median plane. 



The Hyoglossus, thin and quadrilateral, arises from the side of the body and 

 from the whole length of the greater cornu of the hyoid bone, and passes almost 

 vertically upward to enter the side of the tongue, between the Styloglossus and 

 Longitudinalis inferior. The fibers arising from the body of the hyoid bone overlap 

 those from the greater cornu. 



1 The Glossopalatinus (Palatoglossus) , although one of the muscles of the tongue, is mc~e closely associated with the 

 soft palate both in situation and function; it has consequently been described with the muscles of that structure 

 (p. 1139). 





