1126 



TONGUE. 



the transverse at right angles.* Cruveilhier 

 has erroneously described them as passing 

 downwards and inwards: their divergence as 

 they pass downwards is very conspicuous. 

 The central area the lingual nucleus (not/au 

 lingual') of Bauer, is therefore constituted 

 of two sets of fibres, a ventrical and trans- 

 verse ; the transverse being entirely intrinsic, 

 and the vertical in part intrinsic and in part 

 derived from the genioglossus. 



A section made anterior to the free margin 

 of this last-mentioned muscle, shows the cor- 

 tical portion continued completely round the 

 tongue, without the break on its inferior sur- 

 face, occasioned, in the previous section, by 

 the entrance of the genioglossi muscles ; it 

 is also of greater thickness in proportion to 

 the central part, which is comparatively small, 

 and the transverse fibres have a less marked 

 upward curvature at their extremities. 



Thirdly, a section made near the base of the 

 tongue shows the cortical portion nearly lost 

 at the upper surface, greatly accumulated at 

 the sides, but not of so compact a nature as in 

 more anterior situations ; the obliquely ver- 

 tical fibres tolerably abundant, but the trans- 

 verse nearly lost, and the greater part of the 

 inferior surface occupied by the expanded 

 genioglossi. 



Transverse vertical sections, therefore, dis- 

 plav two sets of fibres, a vertical and a trans- 

 verse, and shew their situation and quantity ; 

 let us now see what additional light will be fur- 

 nished by a longitudinal vertical section. It 

 shews that the cortical portion consists of lon- 

 gitudinal fibres, and thus supplies a third set. 

 If the section be made in the middle line, or 

 near it, the whole cut surface is occupied by 

 the vertical fibres of the geniohyoglossus, at 

 first directed backwards, but curving upwards 

 so as to enter the tongue vertically, in which 

 vertical direction they are continued up through 

 its entire thickness, and are lost in the 1 ngi- 

 tudinal fibres of the cortical portion ; if the 

 section is made in the lateral portions, it shows 

 the vertical striation occasioned hy the in- 

 trinsic vertical fibres, and the cortical portion, 

 as in the other. Having ascertained the si- 

 tuation and direction of the three sorts of 

 fibres, we may, by making transverse sections 

 at all points from the apex to the base, and 

 longitudinal ones at various distances from the 

 vertical median plane, and also by tracing the 

 extrinsic longitudinal muscles into the intrinsic, 

 and seeing what part of the one the other fur- 

 nishes, get an exact interpretation of them. 

 We should then find the tongue to consist of 

 the following muscles. 



a. A transverse lingual^, altogether intrinsic, 



* Theile denies the existence of the intrinsic 

 vertical fibres ; he says that those seen in longi- 

 tudinal section are the ascending libres of the genio- 

 glossus, and those seen besides them in trans- 

 verse sections are the most oblique of the transverse ; 

 a misconception of which the microscopical ex- 

 amination of sections at once shows the fallacy. 



f The adoption of the word lingual for all the 

 intrinsic muscles of the tongue, from the French 

 writers on this subject, has no objection against it, 

 and has the advantage of brevity. 



inserted on each side into the submucous 

 fibrous tissue or cutis, continued from apex to 

 base, more abundant anteriorly, where it is 

 horizontal, becoming more curved upwards as 

 we proceed backwards, and being lost at the 

 base. 



. A vertical lingual, in part intrinsic ; in part 

 the lingual portion of an extrinsic muscle, 

 the genioglossus, existing from apex to base, 

 in all parts vertical to the surface, and there- 

 fore, from the curved direction of the tongue, 

 arranged in a more or less radiating or fan- 

 like manner. 



7. A superior lingual, longitudinal, in- 

 trinsic, thin behind, thicker in the middle, 

 and thinner again at the apex, arising from 

 the hyoglossal membrane and cutis at the 

 base of the tongue in a gradual way, and 

 having a similar cutaneous insertion on the 

 upper surface of the tip and neighbouring 

 parts. 



5. A lateral lingual, longitudinal, altogether 

 extrinsic in its origin ; derived from two prin- 

 cipal sources ; one, its upper and most super- 

 ficial portion from the fibres of the stylo- 

 glossus, which pass forward on the side of the 

 tongue after the insertion of that muscle into 

 it, the other from the anterior fibres of the 

 hyoglossus which have a similar distribution : 

 to this may be added a slender fasciculus of 

 fibres interposed between the styloglossus ami 

 hyoglossus, which many modern anatomists * 

 have described as the lingual muscle. The 

 muscle thus formed constitutes the accumula- 

 tion of longitudinal fibres before referred to 

 as seen at the sides of a transverse vertical 

 section of the base ; passing forwards they 

 become fused together and spread out so as 

 to constitute a thin layer, merging above by 

 converging towards the medial plane of the 

 dorsum, in the superior lingual, below in that 

 next to be described, and forming with them 

 a sheath of longitudinal fibres, investing the 

 whole surface of the tongue. 



e. An inferior lingual, a stout fasciculus of 

 longitudinal muscular fibres entirely intrinsic, 

 arising at the base of the tongue between 

 the hyoglossus and genioglossus, and passing 

 forwards between these two muscles to be 

 inserted gradually into the cutis of the tongue 

 on the inferior surface near the apex. This 

 is the true lingual muscle of Douglas and Al- 

 binus, and of anatomists of the present day. 

 I am doubtful whether or not the most an- 

 terior fibres of the genioglossus bend for- 

 wards so much as to become longitudinal, but 

 I think not (though Cruveilhier says they do): 

 if they do, the longitudinal sheath in front of 

 the free margin of the genioglossus would 

 consist of four sets, behind it of three. 



Since the longitudinal fibres invest the 

 whole of the free surface as a sheath ; since 

 they are, most of them, not directly, but 

 obliquely, longitudinal ; and since many of the 

 central spread out to the sides, while the 

 lateral converge to the centre, the division of 

 the longitudinal lingiia/s into superior, lateral, 



* Bichat, Traite' d'Anatomie, t. ii. p. 43. 



