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.
Jumping spiders do sometimes bite, but their venom is not considered to be dangerous (unless youâre allergic to spider bites). They are sometimes mistaken for black widow spiders, but they are far less dangerous. Jumping spiders donât hunt using webs, but they do build a web-like nest called a retreat.