double jointed
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The term double-jointed is an inaccurate way of saying that someone has hypermobility of their joints. Double-jointed would imply that the individual has more joints than normal or that their joints have a twice-normal motion — neither of these is true.

The truth is that people who are called "double-jointed" have joints with more mobility than normal. In some individuals, this is normal. In others, there is an underlying medical reason for the joint laxity.

For example, people with Ehlers-Danlos syndrome have abnormal connective tissue, allowing for excessive joint motion.

Some people can train their joints to have more mobility, and this is often a focus of sports and activities that require great flexibility.  For example, ballet and gymnastics often increase their joint mobility by focused and continued efforts to stretch the ligaments and connective tissue around joint.  On the other hand, people with true hypermobility are born with genetic differences in the make-up of their collagen that allows for the laxity of joints, without every having to try to stretch the tissues.

Also Known As: joint hypermobility, joint laxity

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