what causes double jointedness
(May 2009) Hypermobility, also known as double-jointedness, describes joints that stretch further than normal. For example, some hypermobile people can bend their thumbs backwards to their wrists, bend their knee joints backwards, put their leg behind the head or perform other contortionist tricks. It can affect one or more joints throughout the body.
Common causes of hypermobile joints. Most commonly, hypermobile joints appear without any underlying health conditions. This is called benign hypermobility syndrome since the only symptom is hypermobile joints. It can be caused by: bone shape or the depth of the joint sockets. muscle tone or strength.