'////: Mm Til. :::.7 



t\vn sections, one vertical and longitudinal, the other transverse, there is 

 undiT tin- dorsal mucous membrane, a layer of ivd liluvs, very close in 

 their tt xtuiv, and very adherent to that membrane. Amongst these fibres, 

 then- are some which affect a longitudinal direction, but the majority are 

 \vrtical or transverse, and all are interlaced in the most intimate manner. 

 It appears as if this layer (the //</<///.< .--//y /y/V/W/x of Man) was perfectly 

 independent of the other muscular fibres, whose insertion it receives. It 

 also forms a portion of those which writers have named the intrinsic mil.- ! > 

 of the tongue, and which comprise a superior and inferior, a transverse and a 

 '// 1! Hi/mil is muscle. An attentive examination, however, readily shows that 

 the fibres proper to this snbmucous layer are continuous with those which, 

 coining from a point situated beyond the tongue, form the muscles named, in 

 consequence, extrinsic, and that they arc only the prolongations of these. 

 This division of the tongue into two orders of muscular fasciculi does not, 

 for this reason, possess the importance generally accorded to it. 



Extrinsic in nudes. If the muscular fibres of the tongue appear to be one 



mass in the superior layer just referred to, it is not so when they are 



followed beyond this layer; on the contrary, we see them separate from one 



another, and even admit between them at least in the fixed portion a 



iii amount of adipose tissue, which is particularly abundant towards the 



where it forms a mass called the fatty nucleus of Baur ; then they 



cullect into fasciculi, or perfectly distinct muscles. 



In Sidipods, these muscles number five pairs; 1, The stylo- or Kerato- 

 glossus ; 2, The great hyo- or basio-glossus ; 3, The genio-glossus ; 4, The 

 xinnll kjfo-glottut ' the superior lingual of some authorities); 5, The pharyngc- 

 glossus. 



STYLC-OLOS8U8. 



iimynu. The hyo-glofsus Inngus of /V/v,V/i//. K< rnto-ylnxxiix ,jt,nnif Leyh. 

 lylo-glowu* of Man.) 



This is a very long riband-shaped band, formed of bright-red parallel 

 fibres, and extending from the styloid bone, or large branch of the os hyoides, 

 to each side of the free extremity of the tongue. 



It originates on the external surface of the large hyoideal branch, near 

 its iii ivmity, by a very thin aponeurosis ; and terminates near tin- 



tip of the tongue in expanding over the inferior surface and borders of the 

 . and confounding its fibres with those of the opposite nin 



In the tixed portion of the tongue, this muscle responds: outwardly, tt 

 :,ylo-hyoideus. sublingiial glnud, lingual nerve, and the Whartoninn 

 duct; inwardly, to the genio-glossus and great hyo-glossus muscles. The 

 \\hoV of its free portion is covered by tin- buccal membrane. 



In contracting, this muscle pulls the tongue towards the back of the 

 mouth, and inclines it to one side when acting independently of its fellow 

 on the opposite side (Fig. 149, 1.) 



GREAT HYO-GL088U8 or BASK 



(^i/ru>ijmt.~-Hijo-gl<uutui> // ''mil. Hijx-ijli,**!!* Leyh.) 



\ wide muscle, flattened on both sides, thicker than the preceding, and 

 emiiposed of lihrcs passing obliquely forward and upward, the longest of which 

 Anterior. 



Its origin occupi- s the '\hole side, of the l>"dy <f the os hyni.l, s. fmm the 

 ,iity of th" cm-mi to that of the anterior appendix. It> til.r. -. ;ift< r 



