I would wait a day or two. Sometimes our big guy gets a bit of a limp, and it'll go away after a day or so.

Have you had your dogs hips checked?? I'm not sure about jack russles, but beagles tend to have bad hips (ours does) so he may have hurt his hip?

Our beagle will run, and sometimes if she's running fast she picks up her left back leg and just runs on 3 legs. However, I'm not sure if thats her hips, or just because she's slightly crazy :)

Thanks! This is different than when he might lift his back leg up in the middle of running. He is limping all the time. I have not had his hips checked, what does that mean? Just x rays? He is middle aged. I have some doggie aspirin I can give him.
I'll go Monday if he isn't better.

I'd take him to the vet now. It's quite common for dogs to tear a cruciate ligament in the back leg, and it'll get worse if you allow him to exercise on it over the weekend.

Hopefully he just twisted his leg a bit or bruised it on something, but if he's torn a cruciate, the sooner you deal with it, the better for him.

Laurie

Yup, it's just x-rays. They actually found my dogs hips were bad when they were doing xrays on her stomach. So it's quick and painless. Hers aren't bad enough yet to do anything, they don't seem to bother her 99% of the time, except that she waddles. But she isn't in pain. She probably will get pain as she ages, though.