Joint hypermobility means that some or all of a person's joints have an unusually large range of movement.
People with hypermobility are particularly supple and able to move their limbs into positions others find impossible.
Joint hypermobility is what some people refer to as having "loose joints" or being "double-jointed".
Many people with hypermobile joints don't have any problems, and some people – such as ballet dancers, gymnasts and musicians – may actually benefit from the increased flexibility.
However, some people with joint hypermobility can have a number of unpleasant symptoms as well, such as:
If hypermobility occurs alongside symptoms such as these, it is known as joint hypermobility syndrome (JHS).
Joint hypermobility is often hereditary (runs in families). One of the main causes is thought to be genetically determined changes to a type of protein called collagen.
Collagen is found throughout the body – for example, in skin and ligaments (the tough bands of connective tissue that link two bones together at a joint).
If collagen is weaker than it should be, tissues in the body will be fragile, which can make ligaments and joints loose and stretchy. As a result, the joints can extend further than usual.
JHS is widely thought to be a feature of an underlying condition affecting connective tissue called Ehlers-Danlos syndrome (EDS).
Read more about the causes of joint hypermobility.
Most people with hypermobile joints won't experience any problems and won't require any medical treatment or support.
However, JHS can be very difficult to live with because it can cause such a wide range of symptoms.
People with JHS often benefit from a combination of controlled exercise and physiotherapy, as well as additional help to manage pain and make everyday tasks easier.
The nature of JHS means that you are at increased risk of injuries, such as dislocations and sprains. Managing the condition may therefore also involve treating short-term injuries as they arise, while following a long-term treatment plan to manage daily symptoms.
Read more about treating joint hypermobility.
Joint hypermobility is thought to be very common, particularly in children and young people. Some estimates suggest that around one in every five people in the UK may have hypermobile joints.
In many cases, the joints become stiffer with age, although joint hypermobility and its associated symptoms can continue into adult life.
It's not known how many people have JHS in the UK, as the condition is often not recognised or is misdiagnosed. It's thought to be more common in females than males, and less common in white people than those of other ethnic backgrounds.