Inflammatory process of the testicle, with an acute or chronic course. It can manifest itself, as well as with general symptoms of an infectious character, with imposing local pain and increase in volume and consistency of the scrotum. The most frequent causes of orchitis are of bacterial origin, from germs coming from the urinary tract (sometimes for maneuvers such as catheterization) or from the general bloodstream. A typical form of orchitis is that which follows mumps which, in adult subjects, can cause sterility.