Existing or Determining Causes of Fractures
Fractures by External Violence are divided both clinically and from a mechanic standpoint into two classes: direct and indirect. In fractures by direct violence the bone breaks immediately under the point where the force has been applied. In this class of fractures there is more damage to the soft tissues and this damage is generally more serious than in indirect fractures. Direct fractures are more likely to occur in exposed bones like the clavicle, os calcis, etc.
An example of fracture by direct violence is found in fractures of the tarsal bones after a fall upon the feet from a height.
Under the head of fractures by indirect violence belong (a) those which occur as the result of a rotary or twisting force (spiral fracture of the tibia or fibula, for example); (b) those which are produced by compression; (for example, a fall upon the feet may cause an impacted fracture of the upper end of the tibia); (c) those which are the result of a tearing force.
Fractures resulting from a tearing force occur when a joint is suddenly moved beyond its normal range of excursion. The firmly attached ligaments being a fixed point, the ends or some process of the bones composing the joint are torn off from the remainder of the bone. Examples of this are fractures of the internal or external malleoli, following forcible eversion or inversion of the foot.
Fractures are also caused by muscular action and by gunshot injuries.
Pathologic (spontaneous fractures):
1. Fractures resulting from bone fragility of local origin as for example, tumors, osteomyelitis, aneurisms.
2. Fractures resulting from bone fragility due to some general disease, as for example, tabes dorsalis, paresis, rachitis, osteomalacia, and exhausting chronic diseases.