THE 
VETERINARIAN. 
vol. v. OCTOBER, 1832. No. 68. 
MR. YOUATT’S VETERINARY LECTURES, 
DELIVERED AT THE UNIVERSITY OF LONDON. 
LECTURE XXI. 
The Thorax—the Ribs , Sternum, and Intercostal Muscles—the 
proper form of the Chest. 
The Thorax , or Chest , into which we have traced the wind¬ 
pipe, is of a conoid form, with its apex presenting anteriorly, its 
base posteriorly, and its sides considerably flattened ; or, consi¬ 
dering it in its horizontal position, it is of a somewhat oval figure, 
with its extremities truncated. We may regard the spine as its 
roof; the sternum as its floor; the ribs as its sides; the trachea, 
oesophagus, and great bloodvessels, occupying the space between 
the first pair of ribs, as its anterior extremity, and the diaphragm 
as its posterior boundary. It is supported by the fore-legs; and 
it incloses the heart and the lungs, the origin of the arterial and 
the termination of the venous trunks, and of the collected vessels 
of the absorbents, the windpipe penetrating into it, and the oeso¬ 
phagus traversing its whole extent. 
The Ribs a Protection for the Contents of the Chest. —The 
cavity, whose contents are thus important, ought to be securely 
defended. The slightest glance at the mechanism before you 
will afford sufficient proof of the care which has been taken to 
protect these vital organs from injury. Regard the roof of the 
cavity ; it is not composed of one unyielding prolongation of 
bone, which might indeed have been made strong enough to re- 
sist both pressure and violence from above, but which then would 
have subjected the trunk, and its contents, to a thousand rude 
and dangerous shocks, even in the common action, but more par¬ 
ticularly the rapid motion of the animal; and which would have 
exposed these complicated and delicately-formed organs to dis¬ 
arrangement or rupture : but there is a curiously-contrived series 
of bones, knit together by dense cartilaginous substance, and by 
strong ligaments, and forming so many joints, each indeed pos¬ 
sessed but of little individual motion, but the whole united, form- 
vol. v. 4 I) * 
