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Ligamentous laxity, or ''ligament laxity'', is a term given to describe "loose ligaments." Ligamentous laxity is a cause of chronic body pain characterized by loose ligaments. When this condition affects joints in the entire body, it is called generalized joint hypermobility, which occurs in about five percent of the population, and may be genetic. Loose ligaments can appear in a variety of ways and levels of severity. It also does not always affect the entire body. One could have loose ligaments of the feet, but not of the arms. Someone with ligamentous laxity, by definition, has loose ligaments. Unlike other, more pervasive diseases, the diagnosis does not require the presence of loose tendons, muscles or blood vessels, hyperlax skin or other connective tissue problems. In heritable connective tissue disorders associated with joint hypermobility (such as Marfan syndrome and Ehlers-Danlos syndrome types I-III, VII, and XI), the joint laxity usually is apparent before adulthood. However, age of onset and extent of joint laxity are variable in Marfan syndrome, and joint laxity may be confined to the hands alone, as in Ehlers-Danlos syndrome type IV. In most people, ligaments (which are the tissues that connect bones to each other) are naturally tight in such a way that the joints are restricted to 'normal' ranges of motion. This creates normal joint stability. If muscular control does not compensate for ligamentous laxity, joint instability may result. The trait is almost certainly hereditary, and is usually something the affected person would just be aware of, rather than a serious medical condition. However, if there is widespread laxity of other connective tissue, then this may be a sign of Ehlers-Danlos syndrome. Ligamentous laxity may also result from injury, such as a sports injury or a car accident. It can result from whiplash and be overlooked for years by doctors who are not looking for it, despite the chronic pain that accompanies the resultant spinal instability. Ligamentous laxity will show up on an upright MRI, the only kind of MRI that will show soft tissue damage. It can be seen in standing stress radiographs in flexion, extension, and neutral views as well, and also digital motion X-ray, or DMX. After the images are taken with DMX it is possible to utilize digital radiography to determine the location and frequency of the spinal sprain. Regular X-rays and MRIs do not show ligament sprains. An advantage to having lax ligaments and joints is the ability to withstand pain from hyperextension; however this is also a disadvantage as a lack of perceived pain can prevent a person from removing the ligament from insult, leading to ligament damage. People with hypermobile joints (or "double-jointed" people), almost by definition, have lax ligaments. ==Signs== While ligamentous laxity may be genetic and affect an individual from a very early age, it can also be the result of an injury. Injuries, especially those involving the joints, invariably damage ligaments either by stretching them abnormally or even tearing them. Loose or lax ligaments in turn are not capable of supporting joints as effectively as healthy ones, making the affected individual prone to further injury as well as compensation for the weakness using other parts of the body. Afflicted individuals may improve over time and lose some of their juvenile hyperlaxity as they age. Individuals over age 40 often have recurrent joint problems and almost always suffer from chronic pain. Back patients with ligamentous laxity in the area of the spine may also experience osteoarthritis and disc degeneration. In the case of extreme laxity, or hypermobility, affected individuals often have a decreased ability to sense joint position, which can contribute to joint damage. The resulting poor limb positions can lead to the acceleration of degenerative joint conditions. Many hypermobility patients suffer from osteoarthritis, disorders involving nerve compression, chondromalacia patellae, excessive anterior mandibular movement, mitral valve prolapse, uterine prolapse and varicose veins. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ligamentous laxity」の詳細全文を読む スポンサード リンク
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