Over 1000 patients with traumatic paraplegia or tetraplegia and many more with fractures and dislocations of the spine without damage to the central nervous system have been observed and treated at the Sheffield Spinal Injuries Centre. The vertebral lesions with or without injury to the spinal cord or nerve roots have been classified on the basis of the clinical and roentgenographic findings into five groups: 1. Pure flexion which causes a wedge fracture which is stable. 2. Flexion-rotation which produces an unstable fracture-dislocation with rupture of tue posterior ligament complex, separation of the spinous processes, a slice fracture near the upper border of the lower vertebra, and dislocation of the lower articular processes of the upper vertebra. 3. Extension which causes rupture of the intervertebral disc and the anterior common ligament along with avulsion of a small bone fragment from the anterior border of the dislocated vertebra. The dislocation almost always reduces spontaneously and is stable in flexion. 4. Vertebral compression which results in a fracture of the end plate as the nucleus of the intervertebral disc is forced into the vertebral body and causes it to burst with outward displacement of fragments of the body. Since the ligaments remain intact this comminuted fracture is stable. 5. Shearing which results in forward displacement of the whole vertebra and an unstable fracture of the articular processes or pedicles. Accurate diagnosis and prognosis of the neurological lesion depend on knowledge of the anatomy of the spinal cord and nerve roots, a careful neurological examination shortly after the original injury and repeated examinations thereafter, comparison of the level of spinal injury with the level of paraplegia or tetraplegia, differentiation between paraplegia and tetraplegia of immediate and delayed onset, and the appropriate therapy of the various types and levels of lesion. Simple wedge fractures were treated by bed rest for two to three weeks, mobilization of the back, and ambulation with a back support. Rotational fracture-dislocations in the cervical, thoracolumbar, or lumbar spine were almost invariably associated with tetraplegia or paraplegia. Cervical fracture-dislocations with or without tetraplegia were treated by skull-caliper traction. Thoracolumbar or lumbar fracture-dislocations without paraplegia were treated on a plaster bed for twelve weeks followed by a back support for a few weeks. The thoracolumbar fracture-dislocations with paraplegia were never treated by the plaster bed method but rather by open reduction of the dislocation, and maintenance of the reduction by internal fixation with double plating of the spinous processes. Spontaneous fusion was sufficiently advanced after eight to twelve weeks to get the patient out of bed. If the plates cut out of the bone after twelve weeks, they were removed. Patients with loss of sensation resulting from paraplegia or tetraplegia were turned every two hours to avoid pressure sores. Extension dislocations in the cervical spine, if they had reduced spontaneously, were fitted with a collar to hold the head and neck in sligh flexion for a period of eight to twelve weeks. For dislocations in this region which had not reduced spontaneously, manual manipulation under endotracheal anesthesia was employed. Reduction was maintained by skull tongs applied prior to manipulation. If after four weeks there was roentgenographic evidence of new bone indicating Spontaneous fusion, traction was continued for four to six weeks more followed by a neck collar for an additional six weeks. If new bone did not appear on the roentgenograms after four weeks, anterior fusion was performed followed by skull traction for an additional eight weeks. Vertical compression burst fractures in the cervical spine were treated by skull traction for six weeks followed by a neck collar. In the lumbar spine, burst fractures without paraplegia were treated by immobilization in a plaster bed for eight to twelve weeks followed by back support. The plaster bed was never used in burst fractures with paraplegia. Shear fractures were always associated with complete paraplegia. These fractures were usually stable and did not require operative reduction except when the displacement was great.