Puppy hind leg problem

Question
Hello. I have a shih tzu puppy, 2 months old. But it is too small for a two-month old puppy. Its siblings looks healthier, more active and bigger. Its bark is just a little one. Not like the other puppies. And what made us worry more is that it can't stand its hind legs. It is always spread out straight to its each side. When I try to feel its bones, it seems different from its siblings. What do you think is its problem and how can we cure its legs to make it walk? thank you.

Answer
Greetings, and thank you for contacting All Experts!
It is hard to say what may be affecting this little fellow, but it certainly seems like something requiring a vet's attention. One condition that comes to mind is ''swimmer puppy''. In this condition the puppy almost resembles a turtle when placed on the floor with the hind legs splayed out. Here is a link describing this condition:
http://www.peteducation.com/article.cfm?c=2+2105&aid=884

You need to give this puppy a good surface for good traction like a rug. Avoid slippery surfaces. This condition can be hereditary, so the mother should be spayed or prevented from having any future litters. However, swimmer puppy is not always the case, an abscess in the joint area or a disc issue may also be a culprit for this pup's difficulty walking. Only a vet can really tell what may be going on in this fellow, by seeing the puppy and possibly performing x-rays and other diagnostic tests. I hope this has helped, my very best wishes!