In cases of spontaneous fractures there are no marks of external violence which, if present, would remove the idea of spontaneity.
Fractures of the extremities are not dangerous per se, unless they are compound or occur in old, debilitated, or diseased persons, and they are more severe the nearer they are to a joint. The healing of fractures is more rapid in the young than in the old and in the upper than in the lower extremity. It is not proven that adiposity of itself impedes union.
The question may be asked, how long before examination a given bone was fractured. As a rule, we can only say as to whether the injured person has lived a long or short period since the injury, as the process of repair varies according to age and constitution. No changes occur until eighteen to twenty-four hours, when lymph is exuded. According to Villermé the callus is cartilaginous anywhere between the sixteenth and twenty-fifth days, it becomes ossified between three weeks and three months, and it takes six to eight months to become like normal bone.
The question may also be asked: Has a bone ever been fractured? The existence and situation of a fracture can often be recognized long after the accident, by the callus or slight unevenness due to projection of the edges or ends of the fragments. Where the bone lies deeply covered by soft parts, it is difficult and often impossible to tell, long after union has taken place, whether or where a fracture has occurred.
The answering of this question may sometimes be of importance in identifying the dead, especially in the case of skeletons. In the latter instance by sawing the bone longitudinally we can tell by the thickness, irregularity, or structure of the bone tissue whether a fracture existed, and if it were recent or old at the time of death.
Dislocations call for a medico-legal investigation less often than fractures. They are less common in the old and where the bones are brittle, when fracture occurs more readily. They are seldom fatal per se, unless between the vertebræ or when compound. They may occur from disease in the affected joint or even spontaneously. The diagnosis of a dislocation is easy until it has been reduced, and then it may leave no trace except pain in and limitation of the motion of a joint besides swelling and ecchymosis. These effects are transient, and after they have disappeared it may be impossible to say whether a dislocation has existed on a living body, unless, as sometimes occurs, especially in the shoulder joint, there may be a temporary or permanent paralysis of a nerve and muscular atrophy. After death, the existence of an old dislocation may often be recognized on dissection by scar tissue in and about the capsule.
EXAMINATION AND DESCRIPTION.
The examination of wounds or injuries in a case which is or may become the subject of a medico-legal investigation should be made with particular care and exactness.
As the examination of the wounded person is to give most, and in some cases all, the information to the medical expert on which he is to base his testimony, it should be made with reference to all the possibilities of the case.
The particular variety of wound as described in the foregoing section should be noted, and any peculiarities as to its situation, shape, extent, length, breadth, depth, direction, and the parts involved. Besides these points, the condition of the edges of the wound, whether swollen and ecchymotic, smooth and straight or dentated and irregular, and whether inverted or everted and gaping, are matters of importance. The presence or absence of coagula and clots, the staining of the tissues with blood, the presence of ecchymosis and its comparative age, as shown by its color, should also be noted.