The first rib is the smallest on the horse, but it carries a large supply of nerves that send signals to the front legs. If the first rib is broken, as frequently happens in a fall, or a kick,the swelling may put pressure on these nerves. The pressure can cause paralysis in the front leg. The knee will stay flexed and the toe will drag along the ground. The elbow will actually drop below its normal position. Most horse will make a full recovery with time if the injury is not too severe. DMSO is recommended (you can purchase from my sidebar) by many veterinarians during the healing phase. Structural integration and stress point therapy is crucial to restore a balanced way of going.