THE EXTRINSIC MUSCLES OF THE TONGUE. 



685 



fibres inwards and forwards, it will be necessary to remove from the 

 dorsum. between them and the tip, a thin layer consisting of the 

 mucous membrane with the submucous fibrous tissue, and the fleshy 

 fibivs of the upper lingualis. Beneath the tip a junction between 

 the stylo-^lossus muscles of opposite sides is to be traced. 



The piece of the constrictor muscle (G) which is attached to theofpha- 

 tongue, and the ending of the genio-glossus will come into view on gCuX 

 the division of the hyo-glossus. 



To lay bare the chondro-glossus (p), which is a small muscular of chomiro- 

 slip attached to the lesser cornu of the 

 hyoid bone, turn upwards the dorsum 

 of the tongue, and feel for the small 

 cornu of the hyoid through the mucous 

 membrane. Then remove the mucous 

 membrane in front of this, and the 

 fibres of the muscle radiating forwards 

 will be visible. 



The PALATO-GLOSSUS reaches the side 

 of the tongue at the junction of the 

 posterior and middle thirds. Its fibres 

 are directed inwards, in part on the 

 surface, and in part deeply with the 

 transverse muscle of the septum. 



The STYLO-GLOSSUS joins the body of 

 the tongue below the foregoing, and 

 is continued forwards as a gradually 

 tapering bundle beneath the lateral 

 margin to the tip of the organ, where 

 it becomes united with the inferior 

 lingualis, and meets the muscle of the 

 opposite side. From its upper border 

 fibres are directed inwards over the 

 dorsum of the tongue to the middle 

 line ; and other bundles pass inwards 

 from its lower edge between the fasci- 

 culi of the hyo-glossus. 



The HYO-GLOSSUS enters the under 

 surface of the tongue in its middle 

 third, between the stylo-glossus and 



the inferior lingualis. Its fibres are collected into bundles which 

 turn round the margin and form, with those of the preceding 

 muscles, a layer on the dorsum of the tongue, the hinder fibres 

 passing almost transversely inwards, the anterior inclining forwards gl 

 to the tip. 



The CHONDRO-GLOSSUS is a small Ian-shaped muscle, which arises Chondro. 

 from the lesser cornu and the adjacent part of the body of the hyoid g ' 

 bone. Its fibres are directed forwards, spreading out beneath the 

 mucous membrane of the posterior third of the tongue, and are 

 inserted into the submucous layer. 



FIG. 242. MUSCLES ox THE 



DORSFM OP THE ToNGUE. 



(After Zaglas.) 



A. Superficial lingualis. 



B. Stylo-glossus. 



D. Palato-glossus. 

 p. Chondro-glossus. 

 G. Pharyngeo-glossus. 

 H. Septum linguae. 



Palato- 

 glossus 

 in tongue. 



Stylo- 

 glossus pro- 

 longed to tip 

 of tongue ; 



sends many 

 fibres in- 

 wards. 



Hyo- 

 glossus 



