The subject will be alluded to again, but the fact cannot be learned too early, that these bony (spineous) processes are not intended to bear weight; they represent, as we have expressed it above, the only part of the spine which can be examined and felt, but the spine proper is deep-seated and covered with flesh. If the bony processes belonging to the spine are exposed to pressure, even be it ever so slight, the parts at once become inflamed.

Attachment of ribs
The head of each rib is let into a joint formed between every link in the spinal chain, and the object of this joint is to allow the ribs to move. The diagram also shows that the ribs in front are let into the breast bone, while those behind are lashed, as it were, to each other. These latter are called the false ribs. The former let into the breast bone are the true ribs.

The true ribs are stout and straight, the false are thinner and curved. The curving and arching of the ribs increases from front to rear, so that the chest is narrowest between the two front ribs, and widest between the two last. A true rib is stronger than a false one, and has much less movement, we take advantage in saddle fitting of its being fixed into the breast bone.

The movement of ribs
The ribs move with each act of breathing, the movement, roughly speaking, being forwards and backwards. The ribs in front move very little, those behind move very freely.

Saddle rests on the ribs
When a saddle is placed on the back, it rests on the ribs; it is on the ribs, and not on the spine, that the weight is actually carried. This fundamental fact must early to be committed to memory, it is the basis of all saddle fitting. 

Bones of the loin
Turning now to the loins, we find this part is composed of five bones, which in several respects resemble the links of the backbone, but they are larger, and have growing out from them at right angles a thin long process such as the backbone does not possess, but there are no ribs.   On the length of the transverse processes just described depends the width of the loins. A horse which is narrow in the loins cannot carry weight. Yet the loins are not intended to support weight, no saddle should ever rest on them, they have a function to perform which shall be alluded to later; but the point which we here wish to emphasize is that in spite of the fact that the bones of the loins are larger and stouter than the bones of the back, they are not intended to carry weight.