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.
1 By weight, a strand of spider's silk is heavier and stronger than an equivalent strand of steel! 2  A spider's silk is strong enough to stop a Boeing 747 in its path. 3  Two spider species, the Black Widow and the Brown Recluse, contain venom powerful enough to kill a human!  The fear of spiders is called arachnophobia.