Hypothesis 1-fracture of sesamoids, splint bone, metatarsus

	This is a young foal that may have suffered trauma due to the rapid onset of lameness.  It is possible that the foal was stepped on by the mare.  This would provide enough force to fracture the small bones in the limb of a foal.  No obvious external abnormalities other than swelling and pain and the involvement of only one joint indicate trauma as a distinct possiblity.  If the foal is suffering from a fracture the original break resulted in a hematoma. Callous formation may have started at this point.  The break would cause severe inflammation and the release of inflammatory mediators would cause the severe pain.  In addition horses have very little soft tissue on their lower limbs, therefore any swelling and distension causes the soft tissues to stretch and is extremely painful.  The increased pain after manipulation may be due to soft tissue or displacement of fracture fragments.  This is consistent with the acute nature of a fracture.