Medical Definition of ARTHRODESIS. : the surgical immobilization of a joint so that the bones grow solidly together: artificial ankylosis. the surgical immobilization of a joint so that the bones grow solidly together. ADVERTISEMENT.
Trapdoor spiders are not particularly harmful to man however, like Tarantulas, the tiny hairs on the legs of some species leave tiny red marks where the toothed hairs on the spiders' feet have clung to the skin. Mouse spiders are also a type of Trapdoor spider with huge chelicerae and may measure up to 35mm in body length.
Spider bites are usually harmless. In fact, many bites attributed to spiders turn out to have been inflicted by other bugs. Skin infections also have been mistaken for spider bites. Only a few types of spiders have fangs long enough to penetrate human skin and venom strong enough to severely affect a human being.