In old people bones are more liable to fracture from their brittle condition. Liability to easy fracture occurs in the insane, in nervous lesions as locomotor ataxia and general paralysis of the insane, when the bones are the seat of new growths, in fragillitas ossium, osteopsathyrosis; in the latter disease I have seen the femur fracture by the weight of the leg while resting the foot on a cushion. The liability to fracture depends upon the proportion of organic and inorganic constituents. In disease, the latter may be reduced and predispose to fracture; in the young, the bones are more liable to greenstick or incomplete fracture; and in the old, from excess of inorganic constituents causing brittleness.
A medical man may be required to express an opinion as to whether or not fractures are the result of direct violence, and especially when allegations have been made against attendants on the senile or insane.
The previous predisposing pathological conditions must always be taken into account, and also the amount, if any, of repair that has followed in relation to the time the alleged violence took place.
As the condition of a fracture of the bone of a limb may become a question of considerable importance in medico-legal investigations, the following brief account of the process of repair in fractures is given:
From the First to the Third Day.—The period of inflammation and exudation. Ordinary signs of inflammation and laceration of the parts. Blood will be found extravasated round the fracture, also in the medullary canal mixed up with the fat.
From the Third to the Fourteenth Day.—Gradual subsidence of inflammatory action and growth of the soft provisional callus from the periosteum and surrounding structures, and internally in the medulla, forming a fusiform mass holding the broken ends of the bones together with some degree of firmness. This becomes firmer and almost cartilaginous in density. When the bones are kept immovable, or are impacted, the provisional callus may not be formed. In the case of the ribs the provisional callus is always formed, and Dupuytren‘s “ring of provisional callus” is constant. This may also occur in fractures of the clavicle.
From the Fourteenth Day to the Fifth Week.—Ossification of the provisional callus. The bone is first soft and spongy till the conversion of the soft callus is complete.
From the Fifth Week to some Months after the Injury.—Complete bony union of the fracture and absorption of the provisional callus.
Although the blood clot completely disappears from the immediate neighbourhood of the fracture at an early period, yet layers of dark coagulum may often be found beneath the superficial fascia for four weeks or more after the accident (Erichsen).
It may be of importance to remember this in medico-legal inquiries. The presence or absence of the signs of vital reaction will help to distinguish fractures caused before or after death.