THE OSTEOCLAST

Publisher Summary The large size of the osteoclast, its multinuclearity, and the striated border in contact with absorbing bone form a striking histological picture that suggests that the cells are highly active and expend energy on a large scale. However, even up to the present time, comparatively little is known about their source, function, life span, or ultimate fate, although it is now over a century since their histological features were first described and illustrated. Inquiry into the biology of the osteoclast has passed through two main epochs and has at present entered a third. The typical osteoclast is a large, multinucleated cell, characteristically found on or near bone in process of absorption. This can be physiological, as for instance in the normal modelling of bone, or it can be the result of some pathological cause. The bone around the tooth germs in the embryonic jaw provides an excellent example of physiological absorption.