35 HEAD AND NECK 



direction. Towards the tip of the tongue the rows of conical 

 papillae become more or less transverse in direction, and on 

 the sides of the tongue they are arranged perpendicularly. 



Papilla Filiformes. The filiform papillae are similar in 

 general characters to the conical papillae, but the epithelial 

 cap at the apex of the cone is broken up into thread-like 

 processes. 



Muscles of the Tongue. The tongue is composed almost 

 entirely of muscular fibres, with some adipose and glandular 

 and fibrous tissue intermixed. It is divided into two halves 

 by a median septum, and the muscles in connection with each 



M. glosso-palatinus 



M. stylo-glossus 

 : ^4- Septum linguae 

 M. longitudinal is 



inferior 

 M. hyo-glossus 



M. genio-glossus 



FIG. 132. Transverse section through the posterior part of 

 the Tongue. (From Gegenbaur.) 



half consist of an intrinsic and an extrinsic group. They 

 are as follows : 



t i. Genio-glossus. 

 I 2. Hyo-glossus. 



Extrinsic Muscles, A 3. Chondro-glossus. 



) 4. Stylo-glossus. 



I 5. Glosso-palatinus. 



f i. Superior longitudinal. 



T *. is i I 2. Inferior longitudinal. 



Intrinsic Muscles, -f y , j 



[ 4. Transverse. 



The extrinsic muscles take origin from parts outside the 

 tongue, and thus are capable not only of giving rise to changes 

 in the form of the organ, but also of producing changes in 

 its position. The intrinsic muscles, which are placed entirely 

 within the substance of the tongue, are, for the most part, 

 capable of giving rise to alterations in its form only. 



Dissection. With the exception of the chondro-glossus, the 

 extrinsic 'muscles have been studied already, but the dissector 

 should now take the opportunity of examining more fully their 

 insertions, and the manner in which their fibres are related to 

 one another and to those of the intrinsic muscles. To display 



