Crystalloid Substance and Closed Haversian Canals in the Compact Bone Tissue of Human Bone

Abstract

Fractured surfaces of the human femur, tibia, clavicula, radius, ulna, patella mastoid process of the temporal bone, sternum and squamous portion of the frontal bone were observed by scanning electron microscopy. The results obtained were as follows.
Crystalloid substance was frequently observed in the compact bone tissue. In particular, it was abundant in the long bones of the limbs. The substance was also present in larger amounts in the bones of persons of advanced age than in middle-aged. persons. However, it was not seen in spongy bone tissue with red marrow. The crystalloid substance is considered to reflect senile degeneration in bone metabolism. On the other hand, with increasing age, the Haversian canals were gradually replaced by bone deposition and obstruction of blood vessels frequently occurred in the bones of persons of advanced aged. The osteocytes lodged in the lacunae of the circular lamellae surrounding the Haversian canals became obscure with increasing age.
These morphological changes are together considered to represent senile degeneration, based on a degeneration of blood formation, as a result of decreased bone development. Athough the present experiments were short term, a relationship was demonstrated between deposition of crystalloid substance and blockage of blood vessels which may have some bearing on the problem of human senile bone metabolism.