Shoulderblade Interference

By: Galadriel Billington

10:03PM Jun 9, 2004

	When the horse is standing, the shoulderblade is in "neutral." It is neither forward nor back. This horse has a rather upright shoulder; the neutral position of the shoulderblade may be a little more sloped in many horses.
	As a horse strides, his shoulderblade rotates backward, under the saddle.
	The movement of the shoulderblade takes it fairly deep under the saddle. If the saddle fits the horse well, then it will allow the shoulder to rotate under the saddle with no interference. Again, this horse has a fairly upright shoulder. In a horse with more slope to the shoulderblade, the rotation will be even further under the saddle flap.
	However, if the saddle is too tight, or the flap points inwards, or the flap is held down too tightly by the billets, then the shoulderblade will not be able to rotate smoothly. Instead, the tip of the shoulderblade "bumps" into the front of the flap. The thin skin above the shoulderblade gets "pinched" between the tip of the shoulderblade and the saddle flap. This will be painful. The skin will be tender; imagine giving yourself a big pinch along the ribcage...now take a walk, and pinch with every step you take. The horse will be less likely to extend his leg very far forward, because each time he does, he gets pinched. If the flesh in that area becomes tender enough, it will even be painful after the saddle is removed from his back. The shoulderblade may not be bumping into the saddle flap anymore, but now the shoulderblade is rotating under a muscle that is very tender.
	Each time the horse extends his leg, there is a small trauma to that area of skin. Over time, that area will begin to form a callous, a layer of scar tissue. The most trauma is to the skin closer to the shoulderblade; the scar tissue will not form on the outside, but between layers of skin, under the surface. Because the tissue is under the surface, that scar tissue may even feel like a muscle. It is thick and firm, and there is skin over it which is a little looser. However, it's not firmly attached to any bone, and it's not below a layer of taut skin, so you can pull on it, knead it, etc. It will slide around a bit more than a muscle should, however. Compare the freedom of movement of that tissue with the muscles at the top of the hindquarters. They may also be thick and firm, but they are taut: they do not allow much movement.
	Because the scapula rotates as it goes back, there are several places where it may interfere with the flap. If the saddle is much too far forward, then scar tissue may form just behind the scapula, at the top (yellow). If the saddle is properly placed, but the flap is still interfering with the shoulderblade, then the tissue may form lower and farther back (pink).