First.—Subluxations of the atlas are of rare occurrence.
Second.—All injuries of the cervical spine should be X-rayed.
Third.—An unexpected sudden jolt or jar without any direct blow may be sufficient cause to produce subluxation of the atlas.
Fourth.—The most frequent cause is a blow (oftentimes from a fall) upon the top of the head or upon the back of the neck.
Fifth.—Pressure symptoms may be slight or entirely absent.
Sixth.—The onset of pressure symptoms may be delayed for days and even weeks.
Seventh.—The best classification is one which primarily divides the cases into three main groups. 1. Those in which the displacement is on the horizontal plane (directly forward, backward, to the right or to the left). 2. Those with the displacement on two planes, the horizontal and vertical, namely, the flexion cases. 3. Those with the displacement upon the same plane, but with rotation around the axis.
An absolute line of demarcation cannot be drawn in some cases between these three types, as they are apt to pass to a certain extent the one into the other.
Eighth.—Subluxations of the atlas are associated with fractures in the majority of cases.
Ninth.—In cases not immediately fatal, associated fractures in themselves either of the odontoid or of the atlas, are not of as great significance regarding prognosis as is the support afforded the atlas.
Tenth.—If seen at the time of the accident or shortly afterward, immediate reduction should be made, and a fixation plaster-of-Paris dressing applied.
Eleventh.—Laten treatment is called for in every case with distressing symptoms. When they are not present, leave well enough alone.
Twelfth.—Operative treatment should be advised when other methods fail to relieve symptoms.