Hypermobility
human disease: joints that stretch farther than normal
Hypermobility refers to when human joints stretch further than is usual. For example, some people can bend their thumbs back to their wrist, their toes backwards, put their leg behind their head or any other ways of unusual performances. This condition can affect a particular joint or many joints throughout the human body.
Hypermobility often results from one or more body issues: misaligned joints, abnormally shaped ends of one or more bones near a joint or other body issues. The same defect also results in weaker than normal bones, which may lead to osteoperosis or bone fracture. This condition is often described with the term double jointed.
Some people who are hypermobile have no other health problems.