262 



FIBRO-CARTILAGE. 



To the second class of cartilages belong 

 those of the external ear, of the epiglottis, and 

 the capitula of Santorini, connected with the 

 apices of the arytenoid cartilages, which in the 

 ruminants, the hog tribe, and others, are of con- 

 siderable size. Besides the characters already 

 mentioned which distinguish this class of car- 

 tilage from the former, the microscope dis- 

 closes some further differences. " Placed 

 under the microscope," says Miescher, " the 

 cartilages of this class present a very delicate 

 network, opaque, composed of small round 

 meshes which are filled by a uniform, pellucid 

 substance, and each generally contains a single 

 corpuscle somewhat roundish or oblong/' The 

 cartilages that belong to this class are con- 

 trasted with those of the former, as being never 

 transformed into bone. 



I may add, that in my own examinations of 

 pure cartilage, from the skeletons of cartila- 



r'nous fishes, and from the human subject, 

 have found the foregoing descriptions correct. 

 The cartilaginous corpuscles may be always 

 seen under the compound microscope, with an 

 object glass of a quarter of an inch or an eighth 

 of an inch focus. 



In man and the mammalia, the following 

 structures may be enumerated as belonging to 

 the class of fibro-cartilages: 1. The so-called 

 inter-articular cartilages in the knee, sterno- 

 clavicular, and temporo-maxillary joints; that 

 in the wrist-joint seems to me to be purely 

 cartilaginous. 2. The fibro-cartilages of cir- 

 cumference, as in the hip and shoulder-joints. 

 3. The fibro-cartilages of tendons, which ulti- 

 timately form sesamoid bones, and those of 

 tendinous sheaths. 4. According to Miescher, 

 the tarsal cartilages. 5. The inter-osseous 

 laminae, as those between the pubes, pieces of 

 the sacrum and coccyx, and, in a modified form, 

 the intervertebral substance. 



In the inferior vertebrata and in the inver- 

 tebrata fibro-cartilage gradually disappears : 

 in the former, the intervertebral substance 

 seems to be the only remnant of it, excepting 

 perhaps the sclerotic coat of the eye in some 

 fishes. In the invertebrata, Blainville considers 

 the three tubercular teeth of the leech as being 

 fibro-cartil agin ous . 



Morbid conditions of ^fibro-cartilage. As 

 fibro-cartilage in its physical and vital pro- 

 perties so nearly approaches pure cartilage, it is 

 reasonable to expect a great similarity in the 

 phenomena of disease as they are manifested 

 in the two tissues. Fibro-cartilage appears to 

 be susceptible of reparation in the same man- 

 ner as pure cartilage. (See CARTILAGE.) A 

 substance bearing some resemblance to fibro- 

 cartilage sometimes forms the connecting me- 

 dium between the fractured portions of a bone, 

 where bony union cannot be obtained. 



The phenomena of inflammation and ulce- 

 ration in fibro-cartilages are very similar to 



unfrequently found. Ossification of the nasal 

 cartilages is extremely rare, but in the hog tribe 

 two bones extend from the intermaxillary bone into 

 the cartilage of the proboscis. Vide Miescher, 

 loc. cit. p. 27. 



those in pure cartilage : in the joints these 

 morbid changes are generally complicated with 

 similar diseased conditions of the other tex- 

 tures, either cartilages or bones, whence they 

 are propagated to the fibro-cartilages. It is 

 well known that a condition of the interverte- 

 bral discs, which is commonly spoken of under 

 the name of ulceration, is frequently coin- 

 cident with caries of the vertebrae, having in 

 some instances preceded the vertebral disease, 

 and in others followed it. To Sir Benjamin 

 Brodie we are indebted for the observation that 

 the diseased state of the intervertebral substance 

 has sometimes the precedence of that of the 

 bones; in one case, related by him, where 

 ulceration of the articular cartilages had begun 

 in several other parts, those between the bodies 

 of some of the dorsal vertebrae were found to 

 have been very much altered from their natural 

 structure. He adds, " I had an opportunity 

 of noticing a similar morbid condition of two 

 of the intervertebral cartilages in a patient who, 

 some time after having received a blow on the 

 loins, was affected with such symptoms as in- 

 duced Mr. Keate to consider this case as one 

 of incipient caries of the spine, and to treat it, 

 accordingly, with caustic issues; and who 

 under these circumstances died of another 

 complaint. Opportunities of examining the 

 morbid appearances in this very early stage of 

 disease in the spine are of very rare occur- 

 rence, but they are sufficiently frequent when 

 the disease has made a greater progress ; and 

 in such cases I have, in some instances, found 

 the intervertebral cartilages in a state of ulce- 

 ration while the bones were either in a perfectly 

 healthy state, or merely affected with chronic 

 inflammation, without having lost their natural 

 texture and hardness.' 7 * Otto mentions that 

 he has several times satisfied himself that the 

 destruction of the spine may originally spring 

 from the intervertebral substance ; but he has 

 never found suppuration, unless when at the 

 same time the bones and neighbouring cellular 

 tissue were inflamed.f The anatomical cha- 

 racters of this condition to which we have 

 been alluding consist in an erosion and soften- 

 ing of the fibro-cartilage, frequently attended 

 with the effusion on the surface of a dirty 

 puriform and often fetid fluid. 



Fibro-cartilage is not prone to become ossi- 

 fied; in very old subjects the superficial portion 

 of the intervertebral substances is often ossi- 

 fied, but this is an extension of ossification 

 from the bone or from the anterior common 

 ligament : it is very rare to find any of the 

 inter-articular fibro-cartilages ossified. The 

 ossification of the interpubic fibro-cartilage in 

 advanced age seems to be of a similar nature 

 to that of the intervertebral substances. 



Masses of a substance very similar to fibro- 

 cartilage are sometimes met with accidentally 

 developed ; we find them in or connected with 

 the uterus, in tumours, and in serous or sy- 

 novial membranes. 



( R. B. Todd.) 



* Brodie on the Joints, edit. 2d, p. 231. 

 t Pathol. Anat. by South. 



