The symptoms may be more intense because a condition caused by prolonged weightlessness is usually quite unfamiliar.Space motion sickness was effectively unknown during the earliest spaceflights because the very cramped conditions of the spacecraft allowed for only minimal bodily motion, especially head motion. Space motion sickness seems to be aggravated by being able to freely move around, and so is more common in larger spacecraft. Around 60% of Space Shuttle astronauts experienced it on their first flight; the first case of space motion sickness is now thought to be the Soviet cosmonaut Gherman Titov, in August 1961 onboard Vostok 2, who reported dizziness, nausea, and vomiting. The first severe cases were in early Apollo flights; Frank Borman on Apollo 8 and Rusty Schweickart on Apollo 9. Both experienced identifiable and quite unpleasant symptoms—in the latter case causing the mission plan to be modified. Screen images
This type of terrestrial motion sickness is particularly prevalent when susceptible people are watching films presented on very large screens such as IMAX, but may also occur in regular format theaters or even when watching TV or playing games. For the sake of novelty, IMAX and other panoramic type theaters often show dramatic motions such as flying over a landscape or riding a roller coaster. This type of motion sickness can be prevented by closing ones eyes during such scenes.In regular-format theaters, an example of a movie that caused motion sickness in many people is The Blair Witch Project. Theaters warned patrons of its possible nauseating effects, cautioning pregnant women in particular.
Eponym
This condition is named after the German translation for "snail-pelvis" (Schneckenbecken), this name was first used by Borochowitz et al. when they described a Californian fetus with the symptoms of the disorder and referred to said symptoms as "Schneckenbecken dysplasia". Mouse knockout model
In 2007, Hiraoka et al. created an SLC35D1-knockout mouse model, said experiment revealed that while mice heterozygous for the genetic mutation were born normally without any associated complications, mice homozygous for said mutation died during their neo-natal life. The latter mice had micromelia, craniofacial bone hypoplasia, vertebrae flattening, severely short long bones and iliac bones, Hiraoka noted these symptoms to be similar to those experienced by human fetuses with Schenckenbecken dysplasia, and concluded that this gene must be important for normal ante-natal skeletal formation in mice. See also
Achondroplasia


== References ==