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.
Save. Almost all spiders bite, but fatalities from spider bites are rare, mainly due to anti-venom treatment. A common species, the grass spider, also known as the funnel weaver spider, although venomous to some species, is considered harmless to humans, according to Colorado State University Extension's website.(PlazacCameraman/iStock/Getty Images).rass spiders build silk, funnel-shaped webs among shrubs and grass outdoors or in room corners indoors. Hiding within its web's funnel, a grass spider swiftly ambushes and bites unwary prey straying onto the web.