40 ON DORSO-LUMBAR SPRAIN IN THE HORSE. 
2. From falls, stretching of any of the ligaments, and espe¬ 
cially of the intervertebral, with rupture of the latter, or disunion 
from their adherent surfaces, does not appear to me to be pos¬ 
sible to take place in the direction of the axis of the spine, 
neither from above downward, nor from below upward ; the 
common vertebral ligaments (superior, inferior, and sub-spinal 
dorso-lumbar) are opposed to it. Let us, then, inquire in what 
direction such accidents can happen. 
They can only happen in the lateral direction, because side¬ 
ways there is nothing to diminish or ward off the force of impul¬ 
sion but the intervertebral disc itself. In this way only, as we 
see done every day, in directing force suddenly against one side 
of the spine, while the other remains fixed, have knackers any 
chance of succeeding in destroying the principal bond of union 
between the bodies of the vertebrae. But, does it not happen 
sometimes that a horse falls head-foremost, and comes upon his 
side ? Admitting the possiblity of falls of this description, it is 
easy to understand how such accidents take place. In such 
manner may fracture be produced; though I cannot admit the 
possibility, until I see evidence to the contrary, of luxation , 
which I myself believe to be impossible between these vertebrae. 
Fractures may take place, either in continuity or contiguity 
(a division of them not usually made, nevertheless one which 
I believe necessary). It is a division, however, requiring 
explanation. I do not insist upon the fact of fracture of conti¬ 
nuity, because they are those which ordinarily occur, as I have 
frequently seen in the course of my dissections. Those that I 
call fractures in contiguity are comparatively rare. This 
happens in the ball and socket joint, between one vertebra and 
another. At the same time that the intervertebral disc is rup¬ 
tured, the head and cavity upon the bodies of the vertebrae 
corresponding to it are more or less altered from their normal 
form, either immediately after the accident has taken place, 
or consecutively in the course of the consequent inflammation 
attacking both the exterior and the interior of the articulation. 
3. Violent muscular Efforts may produce rupture of 
the spine. I have known several instances of the occurrence in 
horses that have been cast for operations. M. Rousseau, ex- 
veterinarian-in-chief to the 4th regiment of artillery, has com¬ 
municated to me an analagous case, happening under rather 
extraordinary circumstances, at the time when he was in 
garrison at Vincennes. A horse having the mange had got 
himself underneath the iron bar to which he was fastened up. 
He made a violent effort to disengage himself, in doing which 
he fell over it, and came with force upon the ground, and 
thereby fractured his spine. 
Under the circumstances to which I have adverted, the 
