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.
Most spiders don't bite humans and only do so if they're provoked. When spiders bite, the vast majority of bites only cause a mild reaction in people, such as minor swelling, inflammation, or itching. However, there are a few poisonous spiders in North America that can be dangerous.