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.
The trapdoor spider is a common name for several of these large, harmless spiders that usually nest and live out their lives underground. They make holes or burrows in the ground, line them with silk which they spin, and add a hinged, accurately fitting trapdoor, which is usually made of layers or earth and silk. The opening of the burrow is covered by dirt or gravel, this disguises the entrance to the trapdoor spiders' lair.