This study reports changes in costal cartilages that appear at the microscopic level throughout life, especially during the ossification process. The results show that ossification of costal cartilages can take place in the form of two individual processes, localization and time-separate. Endochondral ossifications in the region of the costochondral zone appear in the first decade and they are sexually dimorphic. Endochondral intramembranous ossifications in the reserve zone appear after the third decade and they are not sexually dimorphic.
They can serve for accurate estimation of age.