1 . Analysis of the twenty-eight cases of spontaneous dislocation of the atlanto-axial joint, not complicated by fracture or by organic disease of the vertebrae, which have been collected shows that the sex incidence is equally divided. The age incidence ranges from two to sixty-two years, with the greatest peak in childhood.

2. The dislocation is preceded by an antecedent infection, most often of the nose or throat, but which may be one of the exanthemata, rheumatic fever, or mastoiditis.

3. Head traction is the best method of reduction and should be followed by a plaster or Thomas collar.

4. Our case is unique in that the patient was an adult of sixty-two in whom there had developed a complete quadriplegia amenable to treatment. The postreduction films showed a good reduction, and a two-year follow-up revealed that there had been no recurrence.

5. Of the many theories offered, that of Berkheiser and Seidler is the most logical in our minds. However, there is one factor that appears to be overlooked,—that is, the probability of an intrinsic factor in the vertebrae. Many people have respiratory infections each winter, yet the incidence of spontaneous dislocation of the atlas is comparatively rare. Adequate post-mortem examination would settle this point. In the absence of this evidence, however, a satisfactory explanation of the pathological process behind the disease must remain lacking.