542 MR. youatt’s veterinary lectures. 
mg a column of such exquisitely-contrived flexibility and strength, 
that, while concussion is avoided, no external violence or weight 
can injure that which it protects. This will occupy our attention 
more particularly when the osseous system comes before us. 
Means by which Concussion is obviated. —Then, as supported 
by and connected with the anterior extremities, observe the con¬ 
trivances there adopted to prevent injurious concussion. There 
is no inflexible bony union between the shoulders and the chest; 
but while the spine is formed to neutralize much of the concus¬ 
sion that might be received—while the elastic connexions be¬ 
tween the vertebrae of the back, alternately affording a yielding 
resistance to the shock, and regaining their natural situation 
when the external force is removed, go far by this playful motion 
to render harmless the rudest motion—there is a provision made 
by the attachment of the shoulder-blade to the chest, calculated 
to prevent the possibility of any rude concussion reaching the 
thorax. 
The muscular Connexion of the Shoulder.— Observe the im¬ 
mense strength, and tendinous clastic composition, of this saw¬ 
shaped muscle, the serratus major , spreading over the internal 
surface of the shoulder-blade and a portion of the chest. A 
spring of easier play could not have been attached to the carriage 
of any invalid. This is a carriage hung by springs between the 
scapulae, and a delightful one it is for easy travelling ; while 
there is combined with it, and the union is not a little difficult, 
strength enough to resist the jolting of the roughest road and the 
most rapid pace. This is not the place to speak of the numerous 
contrivances in the limb below, in order to prevent concussion, 
whether the obliquity and angular position of some of the 
bones ; or the interposition of numerous small bones, each thickly 
covered by elastic cartilages, where the larger bones would other¬ 
wise be vertically opposed to each other; or the admirable con¬ 
trivance of other supplementary and partially detached and 
moveable bones, united to the bony column by elastic ligaments, 
and on which a portion of the weight can occasionally be thrown, 
and no concussion felt:—these will pleasingly and usefully oc¬ 
cupy us when we arrive at the locomotive system. Our atten¬ 
tion must at present be confined to the chest and its immediate 
connexions. Laterally there is sufficient defence against all com¬ 
mon injury by the expansion of the shoulder over the chest from 
between the first and second to the seventh rib; and behind and 
below that there is the bony structure of the ribs, of no little 
strength ; and their arched form, although a flattened arch ; and 
the yielding motion at the base of each rib, resulting from its 
jointed connexion with the spine above, and its cartilaginous 
union with the sternum below. 
