With a side-bone anywhere approaching full development, diagnosis is easy.  The thumb is pressed into the coronet over the seat of the cartilage, when, in place of the elasticity we should normally meet with, we have the solid resistance offered by bone.  In some instances diagnosis is even easier still.  We refer to those cases in which the side-bone stands above the level of the coronet with such prominence as to be readily seen and recognised without manipulation, and where its growth has caused distinct enlargement and bulging of the wall of the affected quarter.  It seems that in such cases the bone-forming process does not end with simply depositing bone in place of the removed cartilage, but that, after that is accomplished, the bone still continues to be produced, as in the case of an exostosis elsewhere.

Although diagnosis in cases such as these is easy, it becomes a very different matter when we are called upon to give an opinion in cases where ossification of the cartilage is only just commencing.  Whether the result of our examination is to decide the sale or purchase of an animal, to determine his fitness or otherwise to enter the show-ring, or to merely advise a client as to whether or no a side-bone is in course of formation, our position is equally difficult, and in either case our examination must be searching.

Perhaps the best advice we can give is to say that the whole of the cartilage must be manipulated both with the foot on and off the ground.  What the reason may be we do not pretend to say, but it is a well-known fact that in many instances the cartilage, with the foot bearing weight, is so rigid as to at once convey the impression that ossification has commenced or is even far advanced.  And yet that same cartilage, with the foot removed from the ground, is as pleasantly yielding to pressure of the thumb as the most exacting of us could wish for.  In any case, then, where doubt exists, the foot should be lifted to the knee, and the cartilage carefully examined with the foot in that position.  If, then, at any spot above the normal contour of the os pedis we meet with hardness or rigidity, we are to look upon that foot with suspicion.  Nevertheless, providing our conscience is sufficiently elastic, the animal may be passed sound so far as the existence of a side-bone is concerned.  We know, however, that with commencing rigidity we may ere long expect one, and if our opinion is asked with regard to that particular, it must be admitted that with rigidity of the cartilage once commenced it is usually not long afterwards before a fully-developed side-bone makes its appearance.