94. And in the last place, the articular processes form so many distinct joints, each being furnished with all the apparatus of a moveable joint, and thus possessing the ordinary provision for the articulation of bones, in addition to the whole of the foregoing securities. 95. "In the most extensive motion of which the spinal column is capable, that of flexion, the common anterior ligament is relaxed; the fore part of the intervertebral substance is compressed, and its back part stretched; while the common posterior ligament is in a state of extension. In the _extension_ of the column the state of the ligaments is reversed; those which were extended being in their turn relaxed, while the common anterior vertebral is now put upon the stretch. In the _lateral inclination_ of the column, the intervertebral substance is compressed on that side to which the body is bent. In the _rotatory_ motion of the column, which is very limited in all the vertebræ, but more particularly in the dorsal, in consequence of their attachment to the ribs, the intervertebral substance is contorted, as are likewise all the ligaments. All the motions of the column are capable of being aided to a great extent by the motion of the pelvis upon the thighs." 96. "The number and breadth of the attachments of these bones," says an accomplished anatomist and surgeon,[4] "their firm union by ligament, the strength of their muscles, the very inconsiderable degree of motion which exists between any two of them, and lastly, the obliquity of their articular processes, especially in the dorsal and lumbar vertebræ, render dislocation of them, at least in those regions, impossible without fracture; and I much doubt whether dislocation even of the cervical vertebræ ever occurs without fracture, either through their bodies or their articular processes. The effects of each of these accidents would produce precisely the same injury to the spinal marrow, and symptoms of greater or less importance, according to the part of the spinal column that is injured. Death is the immediate consequence if the injury be above the third cervical vertebra, the necessary paralysis of the parts to which the phrenic and intercostal nerves are distributed causing respiration instantly to cease. If the injury be sustained below the fourth cervical vertebra, the diaphragm is still capable of action, and dissolution is protracted. The symptoms, in fact, are less violent in proportion as the injury to the spinal marrow is further removed from the brain; but death is the inevitable consequence, and that in every case at no very distant period."