unmistakably proved in the postmortem room. During life they cannot be recognized; that is to say, it is hardly possible to exclude fracture. Anterior, posterior, and socalled abduction-luxations have been observed.

The prognosis is unfavorable owing to injury of the cord. Attempts at reduction should be made by extension and counterextension and direct pressure.

V. FRACTURES OF THE THORAX

(A) FRACTURES OF THE RIBS. (Plates 21 and 22.) Owing to the great mobility of the lowest ribs and the position of the upper ones, protected as they are by the overlying muscles and clavicle, fractures in these two divisions are comparatively rare. Excluding these, however, fracture of the ribs is a very common accident, and constitutes about 15% of all fractures. In children, owing to the exceeding elasticity of the ribs, fractures are very

rare.

Fractures of the ribs are produced by direct and by indirect violence when the thorax is compressed either in its transverse or in its antero-posterior diameter. Multiple fractures occur chiefly in the axillary line and at the angles of the ribs.

The diagnosis is based not so much on the displacement of the fragments as on the presence of pain and crepitus on pressure which is frequently audible. The lung is often injured. It may be directly perforated by a sharp fragment at the time of the fracture; and as the costal and pulmonary pleuræ are injured at the same time, hemothorax and pneumothorax may take place. Traumatic cutaneous emphysema is frequently present, beginning at the seat of fracture, and, in severe cases, extending to the cellular tissue of the entire body. The air escapes into the pleural cavity from the alveoli and tertiary bronchi of the injured

PLATE 21.

Fractures of Ribs.-Fig. 1.-Fracture involving the third to the tenth ribs on the right side. This beautiful preparation, which was taken from a man fifty-three years of age, shows numerous fractures. The right half of the thorax sustained a linear fracture involving the above-named ribs, corresponding approximately to the middle of the affected ribs not counting the costal cartilage; or, in other words, to the axillary line. In all but the eighth and tenth ribs the fracture is found in this line. In addition, the four lower ribs of the preparation -i. c., the seventh, eighth, ninth, and tenth-were fractured at the angle, with considerable displacement; the two upper ones show the traces of an infraction at the same point.

The case, therefore, is one of multiple fracture of the affected ribs. The fractures coincide with the axillary line and with the line of the angle of the ribs. It is evident at a glance that in the three lowest ribs of the preparation (eighth, ninth, tenth) the fractures in the axillary line have united without displacement, while those at the angle present marked displacement. The fourth, fifth, sixth, and seventh ribs present marked deformity (there had been overriding of the fragments in the axillary line), while at the angle no deformity is apparent. The third rib was broken only in the axillary line and shows good union.

Fig. 1 a.-Horizontal section of the fourth rib (axillary) of the same preparation, showing the displacement and firm union.

Fig. 2. Recently united fracture of the ribs without displacement, shown in horizontal section. Callus-formation is well shown.

portion of the lung, during both inspiration and expiration, and spreads from there in all directions. Unless the cutaneous emphysema is universal and becomes dangerous by reason of its extent, it is not a serious symptom. As a rule, it disappears by absorption within a few days. Hemothorax may require aspiration.

Treatment. Complications must be treated as they arise. The region of the fracture is supported with strips of adhesive plaster. Bony union takes place, usually without marked displacement, and in almost every case with only temporary disability. After a fracture of the upper ribs the carrying of heavy burdens on the shoulder