Any advice on the cause and outlook for 'swimmer' puppies known as pectus cavatum. These little cavalier puppies legs are in the position of a turtle's flippers and they 'swim' rather than walk. At 5 weeks only 1 out of our 3 puppies is walking normally, the rest try to stagger to their feet but fall down after a few steps.Their chests are still somewhat flattened. They are normal weight. We are faced with the prospect of having to put them down and are very distressed about this problem. has anyone encountered it before? Can these puppies go on to lead healthy lives? What is the cause? can it be prevented? Advice most welcome.