Various forms of fracture of the body of a vertebra are distinguished:

Oblique fractures are the most common, and show a tendency to marked dislocation (compare Plate 18). The line of fracture is usually directed from above and behind, forward and downward.

Longitudinal fractures are extremely rare.

Transverse fractures are observed in so-called contusionfractures or compression-fractures of the vertebral column; they occur when the column is subjected to extreme flexion and simultaneous compression in its long axis. The least resistant vertebra is compressed by its neighbors on either side; its transverse diameter is increased while its vertical diameter is shortened. True impacted fractures and fissured fractures also occur. Although the outer contour of the vertebral column is, as a rule, but slightly altered in these compression-fractures, a marked narrowing of the spinal canal and contusion of the cord may nevertheless take place, as shown on Plate 19. Fissures and partial or even complete separation of the intervertebral discs have been observed.

Symptoms. A significant phenomenon in fracture of the vertebræ, besides the shock with which such a serious injury is often attended, is the traumatic kyphosis at the seat of fracture. It is the outward expression of displacement of the fragments with shortening of the entire vertebral column, and is produced partly by the injuring force and partly by the contraction of the powerful longitudinal muscles and by secondary movements. An angu

lation on the posterior aspect of the vertebral column is thus produced which is recognized by the characteristic prominence of the affected spinous process. If the fracture is oblique instead of transverse, a lateral dislocation may also take place, corresponding with the direction of the fracture.

A slight grade of kyphosis is often difficult to recognize. Sometimes there is an absence of prominence, and the

PLATE 19.

Double Compression-fracture of the Vertebral Column.— The specimen was taken from the cadaver of a roofer, thirty years of age, who fell from a height of about 60 feet on the 28th of May, 1894. It was said that he first struck with his back against a ladder and then fell on his feet on the gravel beneath. The patient did not recover consciousness until the following day (in the clinic). On admission, there was pain in the upper and lower segments of the thoracic portion of the column; there was no motor paralysis, but sensation was lost on the posterior aspect of the thighs, on the perineum, genitalia, and buttocks. After the second day urine and feces were discharged involuntarily. The case was complicated by a typical compression-fracture of the os calcis on the left side, a deep wound of the soft parts on the posterior portion of the sole of the right foot, and fracture of the right ankle. The subsequent course was marked by decubitus, erysipelas, and amputation of the leg, etc. Death supervened on November 11, 1894. (See Enderlen, in Deutsche Zeitschr. f. Chir., vol. XLIII, p. 329.)

The picture gives a faithful reproduction of the double compressionfracture; the anterior border of the fifth thoracic vertebra is pressed into the sixth; the vertebral canal at this point is intact (Fig. 1 a). The body of the first lumbar vertebra appears completely crushed, the lines of fracture running in all directions. This has produced a marked narrowing of the vertebral canal, which at this point measures only 4 mm. in the sagittal diameter. The cauda equina and its covering are involved at this point (adhesions) (Fig. 1 b).

The fractures were produced by longitudinal compression of the vertebral column in marked anteroflexion. (Author's observation.)

kyphosis can only be recognized by the diminution of the normal lordosis or normal curve of the back. The diagnosis in such cases may be indicated by localized pain on pressure, or transmitted pain by pressure or a blow on the head or shoulder, while the patient is sitting or standing. Abnormal mobility is, of course, never present and crepitus very rarely.

Accessory injuries of the spinal cord or of the nerves that make their exit through the intervertebral foramina may be present in spite of the fact that the spinal cord is