The same misfortune attends those, whose vertebræ of the spine are luxated. For this cannot happen, unless both the medulla, which passes through the middle, and the two membranes, that go through the two processes on the sides, as also the ligaments, that secure them, be ruptured. They are dislocated both backward, and forward; both above and below the transverse septum. As they slip the one way or the other, there will be either a swelling or a cavity behind. If this happens above the septum, the hands become paralytick, a vomiting or convulsions follow, the breath is oppressed, and a violent pain and deafness ensue. If below the septum, the thighs are paralytick, the urine is suppressed, and sometimes it even flows involuntarily. Though a person does not in such cases die so quickly as where the head is luxated, yet it commonly happens within three days; for what Hippocrates has directed in a vertebra luxated externally, that the patient must be laid prone, and extended, and then a person ought to stand upon him with his heel and force it in, must be understood of those, that are but partially displaced, not of these, that are entirely luxated; for sometimes a weakness of the ligaments causes a vertebra to protuberate forwards, though it be not dislocated: this is not mortal. But it is not possible to force it back from the internal part. If any vertebra be reduced from the external side, it generally returns again, unless, which is very rare, the tone of the nerves be restored(26).