My cat is hurt!!

[idrivewhat]

My cat has been hurt, I don't know what happen to him, but he was laying on the steps in the garage and wouldn't move when I let the dogs in, so I pulled him in to the kitchen and got the dogs in.  I noticed a few minutes later that the cat had not moved from the spot where I had left him.  He was looking at me like he wanted my help and I noticed he was trying to get up but was having a really hard time.  He was hurt.  I picked him up and he cried so loud when I touched his hind quarters I almost dropped the poor guy.  
I have examined his legs as best I can, he has some fur missing on the right hind leg, about an inch to two inches long and half an inch wide, a few scrapes on the skin but no other marks.  I test his paw reflex and they all seem normal, he has strength in the back legs, not like it was, but he can use them.  He gets around very very slowly, I have soaked him in epsoms salt bath, for 5 minutes once a day for two days in a row, and that seemed to help him.  He has come out and eaten, but has not gone to the bathroom in 2 days.
Any suggestions?  I don't think anything is broken, but he walks a little differently.

[Aleda M Cheng, D.V.M., C.V.A]

Take him to the vet ASAP!!!

[idrivewhat]

Update on cat!!  After a couple soakings in epsom salts and 4 day rest, Rook was up walking around and in 7 he was back to his old self again,  fur is growing back and he is like new.

Thank you for the advice

[idrivewhat]

Thank you so much for your quick response.  I do have a correction to make, as I just discovered this, he has gone to the bathroom twice, just not when I was looking.  I will call our vet asap.
Thank you again.