The forelegs of the horse are not fitted to the body by means of a joint, but are attached to the trunk by means of large masses of muscle. The trunk is therefore slung between the forelegs, and in this respect differs considerably from the hind legs, which are secured to the body by muscles, and a large cup and ball joints. The muscles which fix the forelegs to the body are plastered over the sides of the ribs to which they are firmly attached; the upper bone of the foreleg, the so-called blade bone, is shaped something like a fan in order to lie flat on the surface of the ribs.

Movements of the blade bone
When the foreleg moves the shoulder blade moves; its range of motion being greater near the shoulder joint than above; the movement of the blade bone is forwards and backwards, it will be easy to observe that while the handle of the fan is going forward, the fan itself is travelling backwards and vice versa, the movement is on the same principle as a see-saw.

Attention must be paid to this fact, as it is apparent that if the blade bone is travelling to and fro, nothing which is placed on the back in the form of a saddle should ever press upon it or interfere with its movements, otherwise the length and safety of the horses stride will at once be affected. So vital is this question that we shall refer to it in greater detail in dealing with the use and function of the different parts of the back.

The muscle pad of the back
The triangular space which lies between the processes of the vertebrae, and the ribs must in the living animal be filled up with flesh or, as we shall prefer to call it, muscle. A large slab of muscle runs the whole length off the back; beginning at the loins it fills the triangular space formed by these vertebrae, and continuing its way along the back fills up the space between the vertebrae and ribs. It is on this muscle that the saddle rests; from a saddle fitting point of view it is the most important muscle of the body

Use of muscles
The use of muscles is to bring about movement, and those which lie along the back have for their special function the lifting of the fore part of the body, as for example in jumping. This, of course, is an exaggerated example of the use of the muscles of the back and loins, but conveys the correct idea of the fore part of the body being lifted; this lifting, though only to a slight extent as compared with the above, is constantly occurring during progression, and maintains the proper equilibrium off the body.