Measurement of the chest gives less reliable results in the lower
animals than in man. A cord four feet long should have one end placed on
a definite point on the withers and not removed until both sides have
been examined. It should be first carried down to a point in the middle
of the breast bone and the distance marked by a knot; a comparison may
be made by carrying to the same point over the opposite side. It should
next be carried successively to the lower end of the 8th rib on the two
sides and the difference marked, and lastly from the lower end of the
third rib to the lower end of the eighth. These measurements should be
made at one stage of the respiratory act, say when the chest is fully
dilated, and similar measurements when the chest is collapsed to
ascertain any difference in the expansion of the two sides of the chest.
In the smaller animals any difference in the expansion of the two sides
may be observed by inspection only, the practitioner standing directly
behind the animal and watching the movements of the two sides from this
standpoint.
A permanent dilatation of one side may be seen in water in the chest
confined to one side, and particularly if of some standing. Complete
hepatisation of one lung gives a similar result. The intercostal spaces
are observed to be wider than usual in such cases, and the movements of
the opposite side of the chest are much more extensive than of the
affected one.
A collapse with limited movement of one side is an accompaniment of
chronic disease of the lung, with wasting of its substance as in cases
of tubercular deposit.