Morphological, histochemical and
ultrastructural investigations on epiphyseal apparatus
of Rana Esculenta were made. The most important
findings were the following: 1) metaphyseal cartilage is
localized inside proximal diaphyseal compact bone as
a plug; 2) metaphyseal cartilage do not reduce in
thickness during ageing; 3) metaphyseal cartilage do
not show vascular invasion and do not mineralize in
degenerative zone; 4) trabecular bone was not at al1
evident in this animal; 5) externa1 periosteum is well
vascularized and proliferates in correspondence to
marginal epiphyseal end of the diaphyseal.
From these results the hypothesis that the ranid
frog bone growth is not due to metaphyseal
metabolism (as in avian and mammals) but to bone
periosteal marginal mineralization is reached
