Another result of an injury which has caused a contusion or contused wound may be a fracture or dislocation. Fractures and dislocations of special parts will be referred to later, in considering injuries of the several regions of the body, but it seems appropriate here to refer to some of those general considerations relating to these injuries which may especially demand the attention of the medical expert.
Fractures may be produced by blows or falls, or from muscular action. The medical witness may be questioned as to the cause of the fracture or, if it was produced by a blow, whether a weapon was used or not, as the defence is likely to assert that it was caused by an accidental fall. The nature of the associated wounds and contusions, if any exist, may, as we have seen, indicate the weapon used. If anything exists to indicate that a fall which caused the fracture was not accidental, this should be noted, as the assailant is responsible for the effects of the fall.
A number of conditions influence the ease with which a fracture is produced and account for a fracture being due to a slight injury, and so are mitigatory circumstances in the case.
Fractures are more easily produced in the old and young, especially the former, than in the adult from the same force. This is due to brittleness of the bones in the old and their small size in the young. Certain diseases like syphilis, arthritis, scurvy, carcinoma, and rickets make the bones more frangible, and there is a peculiar brittle condition of the bones known as fragilitas ossium, more or less hereditary, in which the bones become fractured from very slight violence. Mercer is quoted by Taylor as stating, but on how good authority it does not appear, that in general paralysis of the insane the bones are particularly liable to fracture. Certain it is that not uncommonly insane patients are found dead with single or multiple fractures, but the attendants are generally convicted.
In some parts, like the orbital plate of the frontal bone, the bone is very thin and brittle, but brittleness from any cause only mitigates, it does not excuse.
Taylor[609] reports a case in point where it was proved that the bones of the skull were thin and brittle, and the fractured skull proved fatal from inflammation of the brain. The punishment was mitigated owing to the circumstance of the brittleness of the bones.
Spontaneous fractures may occur from only a moderate degree of muscular action, and even where there is no disease of the bones, but the above-mentioned condition of fragilitas ossium, rendering the bones more brittle, aids in the production of such fractures. The olecranon, patella, and os calcis are particularly liable to such fractures, but the long bones of the ribs and extremities are sometimes so fractured, as instanced in the following cases cited by Taylor:[610]
The humerus of a healthy man has been broken by muscular exertion simply by throwing a cricket ball.[611] In 1858 a gentleman forty years old, during the act of bowling at cricket, heard a distinct crack like the breaking of a piece of wood. He fell immediately to the ground, and it was found that his femur was fractured.
Again, in 1846, a healthy man, æt. 33, was brought to Gray’s Hospital with the following history: He was in the act of crossing one leg over the other to look at the sole of his foot, when something was heard to give way; his right leg hung down and he was found to have received a transverse fracture of the femur at the junction of the middle and lower thirds.
The writer had a case in Bellevue Hospital during the past winter (1892-93) of a man who stated that he had been well and active until some weeks previously, when, from muscular force alone, he sustained a fracture of the neck of the femur. Something abnormal in the bone may be present in such cases.