11-20 



TONGUE. 



that of the neighbouring articulation of the 

 ankle. In fact, on the perfect adaptation of the 

 bones of the leg, at their lower extremities, 

 essentially depends the integrity of the ankle 

 joint itself. 



By the union of the tibia with the fibula 

 the " mortice shaped" cavity, which receives 

 the pulley of the astragalus, is formed, and 

 any injuries which disturb the natural rela- 

 tions of these two bones interfere propor- 

 tionally with the functions of the ankle, which 

 is a perfect angular ginglymus. 



Hence it is, that in some cases of fracture 

 of the lower end of the fibula, a widening of 

 the mortice is produced, from which more or 

 less of permanent deformity and inconve- 

 nience results, abnormal lateral motion being 

 then permitted. The connecting media be- 

 tween the tibia and the fibula interiorly are of 

 extreme strength ; so much so, that no ordinary 

 violence seems capable of rupturing them ; the 

 bones being bound together, not only by the 

 special ligaments of the inferior tibio-fibular 

 articulation already described, but by the 

 annular ligaments and fascia; of the leg also. 

 Hence, as we might infer, the separation of 

 these bones by injury has never been observed, 

 except when the fibula has first been broken. 

 In the " complete dislocation of the 'foot up- 

 wards and outwards, we are furnished with an 

 illustration of the immense strength of the 

 interosseous ligament ; as it is found that even 

 in this severe injury the fibres of this ligament 

 are not usually torn ; but the rough surface of 

 the tibia into which they are implanted is 

 broken off, and carried upwards and outwards 

 with the lower end of the fibula, to which the 

 interosseous ligament still binds it." (See b. 

 fig. 54<. vol. i. page 157 ; article " ABNORMAL 

 CONDITIONS OF THE ANKLE JOINT.") 



{Ben. George M' Dowel.) 



TONGUE. (rX(JfT<rer, Gr. ; Lingua, Lat. ; 

 la Langue, Fr. ; Zunge, Germ. ; Lingua, 

 Ital.) The tongue is a symmetrical muscular 

 organ, situated in the middle line, at the ori- 

 fice of the gastric portion of the gastro- 

 pulmonary mucous membrane, invested with 

 the mucous surface, and subserving to the 

 earlv stages of the process of digestion. 



HUMAN ANATOMY. The human tongue 

 (in common with that of all mammalia) 

 consists of, first, an osseous basis, itself 

 movable, to which it is attached, and with 

 which and on which it moves ; secondly, a 

 muscular system, in part extrinsic, serving to 

 attach it to certain fixed points and to move 

 it on them, and in part intrinsic, constituting 

 the bulk of its substance and moving it on it- 

 self; thirdly, a mucous investment, variously 

 modified in different parts ; fourthly, a. pro- 

 per system of mucous glands ; fifthly, a small 

 quantity of fibrous and areolar tissue ; sixthly, 

 a still smaller quantity of fat ; seventhly, a 

 large vascular supply ; and eighthly, an abun- 

 dant distribution of nerves from three separate 

 sources. 



Size. The size of the tongue is very va- 

 rious. I have examined some tongues of 



adults that certainly were not more than half 

 the size of others, and there does not seem to 

 be any relation between the size of the tongue 

 and that of the individual; but between it 

 and the size of the alveolar arch there is a 

 close relation, and hence we see it generally 

 much smaller in women than in men. It has 

 been generally stated that certain obscurities 

 in speech are caused by too large a tongue, 

 but there do not seem to be any well authen- 

 ticated cases to prove that this supposition is 

 correct. It may in some degree be explained 

 by the fact, that paralysis, which would cause 

 a thickness of speech, would also cause a 

 flaccid half-protruded condition, and, there- 

 fore, an apparent increase of size, of the 

 tongue. 



Direction. In its anterior half it follows 

 pretty much the direction of the lower jaw, 

 that is, it tends forwards and a little down- 

 wards, but behind this it curves downwards 

 and backwards, and ere it reaches the os 

 hyoides has become quite vertical, so that the 

 average of its direction would be downwards 

 and backwards, and its posterior extremity 

 much lower than its anterior. 



Shape. The tongue is of an ovoidal shape, 

 the broad part being behind ; and the character 

 of the curvature in front is parabolic, coin- 

 ciding with the parabolic curve of the lower 

 jaw : it possesses an exact lateral symmetry, 

 and is flattened from above downwards, being 

 thickest towards its base, and thinnest in 

 front. When taken out of the body it seems 

 to be flat, and in the same plane longitudin- 

 ally, but when in situ it possesses a double 

 curvature; one longitudinal, the most consi- 

 derable, by which the upper surface is rendered 

 convex, and by which the posterior part of 

 the tongue is bent from a horizontal to a ver- 

 tical direction ; the other, less considerable, 

 affects the tongue transversely, and renders 

 its posterior part concave in that direction : 

 it is much increased by the contraction of the 

 genioglossi, which draw the centre of the 

 tongue down, or by that of the styloglossi, 

 which draw its sides up. The longitudinal 

 curvature, too, is very much affected by the 

 position of the tongue, for when it is thrust 

 forward, and the hyoid bone raised, the whole 

 organ is much more horizontal, and the cur- 

 vature almost effaced. 



General description. In consequence of 

 its possessing a long axis, and being vertically 

 flattened, the tongue presents for description 

 a superior and inferior surface, two lateral 

 borders, and an anterior and posterior extremity. 



The superior surface, borders, anterior ex- 

 tremity, and anterior third of the inferior sur- 

 face are free ; the posterior extremity and 

 posterior two thirds of the inferior surface are 

 attached. Along the line where the free and 

 attached surfaces meet, we see the investing 

 membrane leaving the tongue, and passing off 

 to neighbouring structures, investing the loose 

 areolar tissue by which in these situations it 

 is underlaid, and forming a system of yielding 

 and movable attachments. Thus at the base 

 the mucous membrane passes off to the an- 



