A. We do recognize that there is likely something causing tremors in the rear legs of geriatric dogs, but we don't understand what it is. The term for this is "idiopathic", and it's observed in multiple breeds (usually medium to large breeds). Sometimes these dogs have low thyroid levels, so I would recommend testing for that (with a full thyroid panel measuring ALL of the thyroid values). But as Dr. Pusateri points out below, other more serious things, such as disease involving the brain, should be considered and ruled out first before it's assumed to be a "normal" aging change.
Your account has been reactivated.