FIBRO-CARTILAGE, feartilago liga mentosay.fibrosa ; Fr. Tissu fibrocartilagineux ; Germ. Faser-Knorpel oder Band-Knorpel).— As early as the time of Galen we find certain organs distinguished by the appellation far vacA; gyrdlop.06, and Fallopius uses a similar term, namely, chondrosyndesmos, as denoting a substance distinct from true carti lage. Haase* also, who wrote in 1747, speaks of two structures different from true cartilage, under the names of cartilagines ligamentosa and cartilogines mister. Bichat likewise recog nised a class of tissues distinct from pure cartilage, and by him it would appear that the name fibro-cortilage was first employed. It is evident that no organ should be classed under the head of fibre-cartilage unless it con sist distinctly of fibrous tissue and cartilage intermixed, and .thus combine nut only the structure but the properties of both, the strength and powerof resistance of the one, and the elas ticity of the other ; nevertheless, we shall find, in examining the various structures which are admitted by anatomists to be fibro-cartilaginous, that the fibrous tissue predominates in such a manner as to justify Beclard in regarding fibro eartilage as a portion of the ligamentous struc ture, which might be designated cartilaginiform ligamentous organs. The distinction was fully admitted too by Mr. Hunter in reference to the texture of the so-called inter-articular car tilages. Speaking of that of the temporo maxillary articulation, he says, " its texture is ligamento-cartilaginous."t The classification of fibro-cartilages adopted by Heckel seems to me to be the best ; he arranges them under three classes :-1. Those whose two surfaces are free wholly or at least in great part, and whose edges are united to the synovial capsules, the moveable Pro-car tilages of articulation. 2. Those which are free by one of their surfaces, and which adhere to bone or tendon by the other : these are the fibro-cartilages of tendinous sheaths, or those which limit the articular cavities, and may be called fibro-cartilages of circumference or cylindrical fibro-eart dirges. 3. Those whose two surfaces are adherent in their entire extent to the bones between which they are placed.
Of these classes the first and third and some of those which come under the second belong to the articulations. Their forms and structure have already been described in the article A ari c u LAT1ON. I may here, however, notice the statement of Weber* in regard to the discs interposed between the vertebrae, which have been generally regarded as fibro-cartilaginous. This anatomist denies that they exhibit any intermixture of cartilaginous substance, and considers that this is rendered manifest by stretching the intervertebral substance, by which it becomes reduced to a fibrous expansion (sehnighautige Masse); he consequently places these intervertebral discs among the fibrous tissues. There can be no doubt that the cir
cumference of each disc is purely fibrous, and that the concentric vertical lamellae of fibrous tissue extend for some distance towards the centre of the disc; but 1 am at a loss to per ceive any resemblance to fibrous tissues in the soft and elastic, and yielding substance which forms the centre. It seems to me that this texture can only be regarded as a modified form of cartilage, differing in its want of density from the ordinary cartilage, whether permanent or temporary. The intervertebral substance, however, to whatever texture it may ultimately be decided to belong, does present very striking differences from the other organs which are placed among the fibro-cartilages.
It is in the fibro-cartilages of the second class that we see most uniformly the inter mixture of the fibrous and cartilaginous texture, although here, likewise, the fibrous tissue pre dominates over the cartilaginous.
The fibro-cartilages are remarkable for their great flexibility, in virtue of which they are enabled to resist fracture, and this property is no doubt owing to the intermixture of fibrous tissue; cartilaginous laminae, on the other hand, are easily broken by bending, and many of them exhibit a fibrous appearance on the surface of the fracture, which, however, arises from the irregular fracture and not from the existence of fibres. Fibro-cartilages are of a dull white colour and quite opaque; they have no perichon drium, but are either in immediate connexion with bone, being inserted into it by their fibrous bundles, or are covered by the synovial mem brane of the joint in which they are enclosed. Their physical and vital properties are those which belong to pure cartilage and to fibrous tissue. Their force of cohesion is very great and surpasses even that of bones. They are more vascular than pure cartilage, but in the natural state they admit very few vessels carry ing red blood. Bichat examined the fibro cartilages in an animal which died asphyxiated, and found these organs not injected. The remarkable manner in which fibro-cartilages resist the influence of a compressing tumour, as a pulsating aneurism, is well known ; while by such means the bodies of the vertebrae are completely destroyed, the intervertebral discs will remain auite uninjured.