Bones become brittle as age increases, and fragility is also induced by certain disordered and debilitated states of the constitution. In some patients, the bones give way on very slight force being applied, after what may have been supposed a rheumatic attack; the thigh is broken by turning in bed, or by walking from the bed to a chair. In one instance, I had put up a fracture of the thigh with a long splint, and in three weeks afterwards the humerus was broken over the end of the splint during an attempt by the patient at change of posture. In many such cases union either does not take place, or is very imperfect.
In children, the bones frequently contain little earthy matter, bend easily, and often break partially on the convexity of the curve. Even at the age of twelve or thirteen, bending of the bones from injury sometimes occur to a great extent, as of the forearm from a fall on the palm of the hand; in adjusting the parts, a slight crackling is heard when they are brought nearly straight. Complete solution of continuity, though more rare, is occasionally met with in very young subjects.
Fractures are generally the result of great force applied directly to the shaft of a bone, or to its extremity; but they are also not unfrequently caused by twisting of the limb whilst the muscles are in a powerful action. Bones are broken transversely; but more frequently there is a degree of obliquity in the fracture, and the fragments are generally detached. A bone may be split longitudinally, as from a musket-ball striking its shaft in the centre; and fissures often extend from a cross break to a considerable extent, sometimes into joints.
Swelling is often rapid, from extravasation of blood; at other times it is slow, and of a serous character. At first it is soft and yielding, but after a time painful inflammatory tumescence supervenes, the violence and extent of which will depend on the severity of the injury, and very much also on the treatment to which the parts are subjected. If the bones be put as nearly as possible into their original position, and retained so, judiciously—the limb being laid in a comfortable and unconstrained posture, and the bandages, splints, &c., properly adapted—little or no pain or inflammatory swelling will occur; no more action ensues than is required for reparation of the injury. If, on the contrary, the bones are allowed to remain unreduced—perhaps after being well handled—their broken ends, laying among the soft parts, are pulled out by violent spasms, lacerations of the muscles and vessels is increased, effusion, swelling, and violent inflammatory action occur, the pain becomes excruciating, fever and delirium follow; there is an imminent risk of gangrene, and extensive suppuration among the muscles is almost inevitable. If the patient recover, the union is bad, and the limb deformed.
A fracture is said to be simple, where there is no wound of the superimposed integuments. The external parts may be bruised, or the deep structure much injured, with laceration of the vessels and rapid and great swelling; or there may be little or no injury of the soft parts. Great danger may exist without division of the integuments; these, yielding under the force, may remain entire, whilst by great and direct violence the bone is comminuted, the muscles broken up, and the vessels and nerves torn,—the limb is infiltrated with blood, and must become gangrenous as soon as reaction takes place. But usually these untoward circumstances do not exist in simple fractures, the soft parts being but slightly injured.
Fracture is compound when the integuments are divided by the external force, so as to expose the broken bone. But the wound may not penetrate to the bone; and then the accident is termed fracture with wound, not compound fracture. The soft parts are often divided by the sharp end of the bone; this is frequently the case in oblique fracture, occasioned by a fall from a height, the lower fractured extremity being pushed forcibly upwards. The muscles are usually much injured. The wound is either large or small, lacerated or clean.
Fracture, simple or compound, is comminuted when the bone is divided at the broken point into fragments, either small and loose, or large and adherent to the covering of the bone and other soft parts.
Fracture may be complicated with wound or displacement of a neighbouring joint, and with laceration of large bloodvessels and nerves.
