

NORMAL HISTOLOGY. ^jfr* 



[brans layer of dense fibre-elastic tissue and an inner, much 

 looser stratum, between the fibres of which are numerous connective- 

 tissue cells. This inner portion is intimately concerned in the pro- 

 duction of new cartilage, and is known as the chondrogenetic layer. 

 The cells of the latter arrange themselves in rows parallel to the 

 surface, and gradually assume the characteristics of the cartilage 

 corpuscles, being at first spindle-shaped, but gradually assuming the 

 more spherical form. The new cells soon become surrounded by the 

 recently-formed matrix, which, at first small in amount, soon in- 

 creases so that the groups of cartilage- cells become separated by 

 more extensive tracts of intercellular substance ; as the nests of cells 

 formed by the division of the original single occupant of the lacuna 

 recede from the perichondrial surface they lose their primary parallel 

 disposition and become irregularly arranged and further separated. 

 Sometimes in those portions most removed from the perichondrium 

 the ground-substance appears granular; this feature is intensified 

 when a deposition of calcareous matter takes place, which not infre- 

 quently happens in old subjects. 



Elastic cartilage is distinguished by the presence of elastic 

 fibres within the intercellular substance. The typical hyaline matrix 



is confined to areas of 

 limited extent immedi- 

 ately surrounding the 

 cell-nests, while the in- 

 tervening matrix is 

 penetrated by net- 

 works of elastic 

 fibres extending in all 

 directions. The cells 

 within the lacunae, in 

 the midst of the hy- 

 aline areas, resemble 

 closely the usual ele- 

 ments of hyaline car- 

 tilage. Elastic cartilage 

 has a much less general 

 distribution than the 

 hyaline variety, occur- 

 ring principally in the 

 cartilages of the ex- 

 ternal ear, part of the 

 Eustachian tube, epi- 

 glottis, arytenoid cartilages, cartilages of Wrisberg and of Santorini. 

 This tissue presents an opaque, yellowish tinge in contrast to the 



FIG. 51. 



FIG. 52. 



Elastic cartilage from the epi- 

 glottis : c, cartilage-cells sur- 

 rounded by a very limited area of 

 hyaline matrix (K) ; the remaining 

 part of the intercellular substance 

 is penetrated by net-works of 

 elastic fibres (e), cross-sections of 

 which appear as minute points. 



Fibro-cartilage from the 

 knee-joint : c , cartilage- 

 cells surrounded by very 

 limited areas of hyaline 

 matrix (h) ; the space be- 

 tween these areas is occu- 

 pied by the fibrous tissue. 



