The Causes of Fractures are divided into Predisposing and Remote.

In the first class are comprehended the situations and functions of the bones, the age of the patients and their diseases. Superficial bones are more easily fractured than those which are covered by a considerable quantity of soft parts, while the functions of some bones render them more liable to be fractured than others; for example, the bones of the leg.

Again, the gradual increase of the quantity of the phosphate of lime in the structure of the bones makes them brittle in proportion as years advance, so that in old age the proportion of the inorganised to the organised part is so great that the bones are fractured by the slightest causes. Therefore in puppies the animal and organised part bears a greater proportion to the earthy, and the bones, being consequently more elastic and flexible, are not so easily broken as in old age Now several writers set down cold as a predisposing cause of fractures. This doctrine has originated from these injuries being more frequent in the winter time. But this is erroneous, since in cold countries these observations are contradicted and denied, both in man and the lower animals.

The remote cause of fractures is external force variously applied in falls, blows, kicks, etc.