koski1968 BAUME

Volume 54
Number 8
Cranial growth centers 577
seal growth apparatuses only the degenerative zone is mineralizing.70 Finally,
the so-called primary spongiosa, always present in the long bones, seems to be
absent in the condyle.33a TO
In regard to the function of the condylar cartilage, differences have been
found to exist between it and the epiphyses. The condylar cartilage is highly
responsive to mechanical stimuli79 8a I51 I6 and responds differently from the epiphyseal
cartilages to various hormonal and chemical agents.?’ 32~ 6g
The decisive point is the question of the tissue-separating force or the independent
growth-promoting potential. As mentioned earlier, the existence of this
force or potential has been implicit in the interpretation of the function of the
condylar cartilage in most descriptions of the condyle. This problem can again
be tackled by way of transplantation. If the condylar cartilage is transplanted
to a relatively nonfunctional site, such as the subcutaneous or brain tissue, it
does not maintain its structure and does not behave like the condylar cartilage
in sit@+ 68 (Fig. 11). Only when it is accompanied by a piece of adjacent
bony ramus may the transplant grow, and even then the structure is not maintained
in the beautiful manner observed in transplanted epiphyseal cartilages249
45847348 (Fig. 12). Tissue-culture studies have also demonstrated lack of
growth of the condylar cartilage.6o
Thus, these experiments have furnished evidence for the lack of growth
potential in the condylar cartilage, and the condylar cartilage does not seem
to fulfill the definition of a growth center.
Actually, the opinion that the condylar cartilage and its growth would be
of major importance for the growth of the mandible, let alone the face as a
whole, appears rather odd, considering the known facts. To a la,rge extent, the
mandible grows in size by periosteal and endosteal apposition and remodeling
resorption.14* 2os 64p *Or Q 83~ 9o Furthermore, it seems obvious t.hat this bone consists
of several relatively independent parts, whose existence and growth depend on
different factors39 2gg 85 These facts already speak strongly against the simple idea
that the growth of the mandible would be dependent on growth at the condyle,
located in one corner of the curved bone.
There is a great deal of further clinical and experimental evidence against
Fig. 13. A schematic illustration of the effect of a condylar resection in monkey (based on
Sarnat’s illustrations). The black point represents the mental foramen, which has been used
as the point of superimposition; the alveolar margins have also been superimposed.