Article Type

Original Study


Background : the calcaneus clearlydemonstrates the characteristicsofossification processes that arefoundin both short and long bones.Cartilagecanals are found in the epiphysisof long bones and in smallandirregular bones, but their role inossificationprocess have not beenestablished.Aim of the work : to study the developingcalcaneus and to clarify theroleof cartilage canals in the boneformingprocess.Materials and Methods : Twentyfour human fetuses were used in thisstudy in 9th, 10th, 13th, 15th,19th, 22nd and 24th weeks of gestation.Sagittal sections were prepared from the calcaneus and stained withhaematoxylin & Eosin, alcian blue &periodic acid Schiff reagent and Mallorystains. Results : In 9th week-aged fetus,the calcaneus showed undifferentiatingcells with no cartilage canals. In10th week-aged fetus, the cartilagecanals began to originate from theperichondrium. In 13th week-aged fetus,there was an area of proliferatedcartilagecells which were arrangedingroups. The cartilage canals comprisedconnective tissue, blood vesselsand were surrounded by collagenfibers and exhibited +ve PASreaction.In 15th week-aged fetus,there was hypertrophied chondrocytesarranged in small groups. In 17week-aged fetus the hypertrophied cartilage cells in the center of thecalcaneus were arranged in pairs orsmall groups surrounded by expandedareas of pale basophilic matrix. In19th week-aged fetus the perichondralossification center appeared. In22nd week-aged fetus the endochondralcenter of ossification appearedinthe form of ossified matrix aroundcartilagecanal with marrow spaces.Increasedpatches of basophilic matrixaround hypertrophied chondrocyteswere seen. In 24th week–agedfetus the perichondral center and theendochondral center of ossificationbecame more developed. The primarycenter of ossification showedlargeareas of bone formation in theformof specules or trabeculationseparatedby areas of marrow spacesfilled with blood cells. The cartilagecanals showed significant progressiveincrease in both numberandsize. Cartilage canals showedthindiscontinuous wall at more advancedages of gestation. Conclusion : Cartilage canals areinvolved in the nourishment of thecartilage cells as well as in the ossificationprocess. Calcanean endochondralossification center was detectableat 22 nd , 24th weeks ofgestation so, it is recommended to be used as a mean to evaluate gestationalage in late pregnancy by ultrasonography.

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Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.