ture. There may be only a linear division, without any displacement or disfiguration of the external shape of the bone (fissure). (See Figs. 1 and 2.) This variety is

observed in the cortex and at the base of the skull; in the superior maxilla and the scapula; seldom in the long bones.

STATISTICS.

Statistics show that fractures of the bones of the extremities, including those of the clavicle, represent three-fourths, while those of the bones of the trunk comprise but one-sixth, and those of the skull but onetwenty-fifth, of all fractures.

Fractures of the upper extremities are twice as frequent as those of the lower. Most frequent are the fractures of the forearm, 18 per cent.; then follow those of the leg, of the ribs, and of the clavicle, 15 per cent.; hand, 11 per cent.; humerus, 7 per cent.; femur, 6 per cent.; foot, 2.6 per cent.; face, 2.4 per cent.; skull, 1.4 per cent. ; patella, 1.3 per cent.; scapula, spinal column, and pelvis, less than 1 per cent.; sternum, 0.1 per cent. Most fractures occur between the thirtieth and fortieth years. Fractures are four and a half times more frequent in men than in women.

SIGNS OF FRACTURES.

The symptoms of a fracture are represented by a chain of mechanical disturbances, set up by the solution of the continuity of the bone. The most important of these are abnormal mobility, crepitus, functional disability, deformity, ecchymosis, and pain.

1. Abnormal mobility is the most characteristic sign of the presence of a fracture. It is absent in the incomplete variety (fissures, infractions, etc.; see Figs. 92, 137), and also in impacted fractures-for example, in impacted fracture of the neck of the femur. (See Fig. 107.) In fractures of the ribs and the short bones unnatural mobility is also often looked for in vain.

2. Crepitus is the peculiar sensation felt when friction is caused between the two separated bone-fragments. Crepitus is, of course, absent when there is no abnormal mobility, since the production of the characteristic friction presupposes the mobility of the fragments. Consequently, also, there is no crepitus in

fissures and infractions (green-stick fractures), nor in impacted fractures. Crepitus is also absent in cases of the wide separation of the fragments, whether this be caused by diastasis (fracture of patella or olecranon), or by the interposition of fascia or muscular tissue between the displaced fragments. These circumstances will prevent mutual contact between the ends of the fragments. In other cases the fragments overlap each other to such an extent that contact between the broken ends is impossible (longitudinal displacement; compare p. 18), or sharp and displaced. bone-fragments are driven into the muscular tissue, so that thus an interposition of soft tissues between the broken ends of the bones is produced.

3. Functional disability is seldom absent. Its extent naturally depends upon the shape and kind of the bone as well as of the fracture. This is shown in the cases illustrated by figures 72 and 123. There are individuals inured to pain who are able to use their arms notwithstanding the fracture of both radii, or who are able to walk a short distance in spite of having sustained a malleolar fracture; but such occurrences are to be regarded as very exceptional. Still, from a legal point of view the knowledge of such possibilities is of the utmost importance.

4. Deformity is present in those fractures wherein more or less displacement of the fragments has taken place. Consequently, it will not often occur in cases of fissure or in infractions; in other words, in fractures where neither abnormal mobility nor crepitus is to be found.

Thus it can be seen that the three important signs, abnormal mobility, crepitus, and deformity, usually go

together. It must be added that wherever deformity indicates more or less displacement, shortening of the broken bone is seldom missed.

5. Ecchymosis is naturally most marked in direct fractures. It is produced by the laceration of small blood-vessels and of the medulla of the bone. If the fracture extends into the joint, there is always an extravasation of blood within the joint (hemarthrosis). Ecchymosis is generally more marked a few days after the injury is sustained.

6. Localized pain is a constant symptom of fracture. It is increased by pressure and by every active or passive effort that displaces the fragments.

DIAGNOSIS.

In most cases the presence of a fracture can be recognized even by simple inspection. (Compare Fig. 33.) If the trifolium—abnormal mobility, crepitus, and displacement-is present, the proof of fracture is established beyond doubt. The value of inspection should not be underestimated. In fact, the part should be inspected very thoroughly before palpation is resorted

to.

The custom of handling an injured organ by pressing, turning, and squeezing before it is carefully looked at can not be condemned too strongly. It pays very well to inspect the injured area for some length of time, and to compare it with the normal outlines of the opposite side, until there is a clear idea of the condition of things in the examiner's mind.

But if there be an infraction or a fissure or an impacted fracture, or in cases where one of two parallel

bones is fractured (forearm, for instance; see Fig. 60), or if the break has occurred near a joint, or if there be extensive inflammation, the diagnosis may be very dif ficult, and the injury may be mistaken for a contusion or a distortion, or even a dislocation.

As to dislocation, it should be borne in mind that this injury does not lead to any abnormal mobility nor any shortening of the bone-shaft.

While it is often

In contusions the absence of abnormal mobility, crepitus, displacement, and shortening will be observed. It is obvious that these differential points are mainly to be elicited by manual examination. This process being always productive of more or less pain, it should be performed with a great deal of care. possible to diagnosticate the presence of a fracture by means of careful palpation, conclusions as to its direction and as to the size of the broken fragments could seldom be drawn in the pre-Röntgenian era unless the patient was anesthetized. If there be abnormal mobility, manual examination will naturally yield crepitus also.

Whether or not there is shortening of the limb can be ascertained by measurement. It must be borne in mind, however, that the points from which measuring with a tape are begun fail to show mathematic exactness and regularity. They are represented by roundshaped bony protuberances, like the anterior superior spine of the ilium, the major trochanter or the external condyle of the femur, the external malleolus of the fibula, the styloid process of the radius, and the olecranon and acromion in the upper extremity.

This variation in position of the points of measurement explains why an error to the extent of a whole. inch can easily be made. With the employment of all