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Interface between intramembranous and endochondral ossification in human foetuses
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Abstract
In the head and neck of human mid-term foetuses, the interface between areas of endochondral ossification and adjacent membranous (intramembranous) ossification is extensive. Using 8 foetal heads at 15–16 weeks, we have demonstrated differences in the matrices and composite cells between these 2 ossification processes, especially in the occipital squama and pterygoid process. Aggrecan-positive cartilage was shown to be invaded by a primitive bony matrix that was negative for aggrecan. At the interface, the periosteum was continuous with the perichondrium without any clear demarcation, but tenascin-c expression was restricted to the periosteum. In contrast, the interface between the epiphysis and shaft of the femur showed no clear localisation of tenascin-c. Versican expression tended to be restricted to the perichondrium. In the pterygoid process, the density of CD34-positive vessels was much higher in endochondral than in membranous ossification. The membranous part of the occipital was considered most likely to contribute to growth of the skull to accommodate the increased volume of the brain, while the membranous part of the pterygoid process seemed to be suitable for extreme flattening under pressure from the pterygoid muscles.
Abstract
In the head and neck of human mid-term foetuses, the interface between areas of endochondral ossification and adjacent membranous (intramembranous) ossification is extensive. Using 8 foetal heads at 15–16 weeks, we have demonstrated differences in the matrices and composite cells between these 2 ossification processes, especially in the occipital squama and pterygoid process. Aggrecan-positive cartilage was shown to be invaded by a primitive bony matrix that was negative for aggrecan. At the interface, the periosteum was continuous with the perichondrium without any clear demarcation, but tenascin-c expression was restricted to the periosteum. In contrast, the interface between the epiphysis and shaft of the femur showed no clear localisation of tenascin-c. Versican expression tended to be restricted to the perichondrium. In the pterygoid process, the density of CD34-positive vessels was much higher in endochondral than in membranous ossification. The membranous part of the occipital was considered most likely to contribute to growth of the skull to accommodate the increased volume of the brain, while the membranous part of the pterygoid process seemed to be suitable for extreme flattening under pressure from the pterygoid muscles.
Keywords
endochondral ossification, intramembranous ossification, aggrecan, versican, tenascin-c, pterygoid process, occiput, human foetus
About this articleTitle
Interface between intramembranous and endochondral ossification in human foetuses
Journal
Issue
Article type
Original article
Pages
199-205
Published online
2014-06-02
Page views
2032
Article views/downloads
2784
DOI
10.5603/FM.2014.0029
Bibliographic record
Folia Morphol 2014;73(2):199-205.
Keywords
endochondral ossification
intramembranous ossification
aggrecan
versican
tenascin-c
pterygoid process
occiput
human foetus
Authors
S. Hayashi
J. H. Kim
S. E. Hwang
S. Shibata
M. Fujimiya
G. Murakami
B. H. Cho
