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.
Often found around houses in areas lit by artificial lighting at night, cat-faced spiders may look somewhat creepy but theyâre not poisonous. (image via: Tocayo750) Cat-Faced Spiders are rather small; only about 1/5 of an inch wide, and the females are much larger than the males.