Anatomy And Physiology

Anatomy Physiology

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Hyper-mobility Syndrome (HMS) is diagnosed when a patient is hyper-mobile in one or more joints, and other symptoms are also present.  Women and children are more susceptible than men, as are certain ethnicities.  Sometimes the syndrome recedes with time.  Other times it may be a symptom of a more debilitating disease.

What is Hyper-mobility?

Hyper-mobility, commonly known as being double-jointed, is simply a condition where a joint easily moves beyond the normal expected range. Examples are knees or elbows that flex backward, the ability to touch your wrist with your thumb, or wrap your leg around the back of your head. 

Many children, perhaps as many as 15%, have hyper-mobile joints.  This is due to their greater natural flexibility.  Most outgrow the condition without exhibiting other symptoms that signal the Hyper-mobility Syndrome, or HMS.

Women of childbearing age are also prone to hyper-mobility, particularly just prior to menstruation and during the third trimester of pregnancy.  This is due to normal hormonal changes in collagen, a protein that essentially glues joints together.  It is usually short-lived.

Another common cause of hyper-mobility is ill-formed joints.  Hips and shoulders are prime candidates, as they are both ball-and-socket joints.  If the socket is very shallow, the joint will have a much greater range of motion than normal.  It will also be weaker, needing more ligament and muscle strength to prevent dislocation.  This is usually genetic.  Another genetic cause is longer, weaker ligaments.  Ligaments tie joint bones together.  If they are inherently weak, the joint will have much greater range of motion – and less strength.

Hyper-mobility in itself does not signal HMS.  It will often correct itself with time, and/or can be controlled with diet and strength conditioning.   It can, however, be debilitating as the affected joints are weak.  Hyper-mobile joints are prone to injury and damage such as sprains, strains, and dislocations.  Scoliosis, osteoarthritis, and other problems occur more frequently.

What are the symptoms of HMS?

Symptoms of true HMS include joint instability causing frequent injury; frequent sprains, tendonitis, or bursitis when performing normal activities; early-onset osteoarthritis; frequent dislocations, especially in the shoulder; joints that make clicking noises, like TMJ; chronic fatigue and/or dull pain in hips, back, or knees; increased nerve compression disorders like carpal tunnel syndrome; and pain that does not respond well to normal doses of anesthetic or pain medication.  Other symptoms include unusual skin stretchiness or changes in skin elasticity, and thin scar formation in the skin that looks striated.

When a patient exhibits such symptoms, doctors must rule out other medical conditions that exhibit similar symptoms.  These include fibromyalgia, rheumatoid arthritis, Ehlers-Danlos syndrome, Marfan syndrome, lupus, polio, and others.

How is HMS diagnosed?

Doctors are still learning to recognize true Hyper-mobility Syndrome, as opposed to simple hyper-mobility.  According to , well-defined criterion for diagnosing HMS has just begun to be universally implemented.  Tools for diagnosis include the Beighton Scoring system, and the Brighton Criteria.

The Beighton Scoring System has been used for more than thirty years.  A high Beighton score by itself does not indicate HMS, just widespread hyper-mobility.  A Beighton score of 4/9 is considered high.  To score, one point is added for each of the following:

* Placing flat hands on the floor with straight legs
* Left knee bending backward
* Right knee bending backward
* Left elbow bending backward
* Right elbow bending backward
* Left thumb touching the forearm
* Right thumb touching the forearm
* Left little finger bending backward past 90 degrees
* Right little finger bending backward past 90 degrees

Diagnosing HMS begins here.  Doctors then apply the Brighton Criteria, developed in 2000 and quickly becoming a universal benchmark tool. However, it has only been validated in adults.  Children are much more difficult to diagnose.

According to Professor Rodney Grahame of UCL Hospitals in London ( ), “the Brighton Criteria is arranged in Major and minor criteria.  HMS is diagnosed in the presence of two major criteria; or one major and two minor criteria; or four minor criteria.  Two minor criteria may suffice if the patient has a HMS-diagnosed first-degree relative.”

Major criteria include:

* A Beighton score of 4/9 or greater, showing widespread hyper-mobility.
* Arthralgia (joint pain) for longer than 3 months in four or more joints.

Minor criteria include:

* A Beighton score of 1/9, 2/9, or 3/9 (especially over age 50).
* Arthralgia for longer than 3 months in one to three joints.
* Chronic back pain for longer than 3 months.
* Dislocation or subluxation (partial dislocation) in more than one joint, or
* Dislocation or subluxation in one joint on more than one occasion.
* Soft tissue rheumatism like bursitis or tendonitis, more than 3 lesions.
* Marfanoid body structure.
* Abnormal skin stretchiness, thin skin, especially with striated scarring.
* Eye signs: drooping eyelids, myopia or antimongoloid slant.
* Varicose veins, hernia, or uterine/rectal prolapse.

How is HMS treated?

Physical fitness is crucial to prevent injury to weak joints.  A regular exercise program that incorporates both strength conditioning for muscle tone, and cardio-vascular training for healthy blood flow, is necessary.  Some incorporate physical therapy as well.  Many benefit from hydrotherapy, or exercising in water, to reduce joint concussion.  Low-impact exercises like Pilates or Tai-Chi are of far more benefit than high-impact exercise or contact sports.  Isometric exercises are particularly helpful in some cases.

Medications to reduce pain and inflammation are frequently prescribed.  These include analgesics and anti-inflammatory drugs, like aspirin and Motrin. Other treatments that are sometimes helpful are steroid injections, tricyclic anti-depressants, benzodiazapines, and Tramadol – a non-narcotic opioid.

Patients are encouraged to find, and maintain, their ideal weight through a sensible diet.  Being overweight adds stress to weak joints.  Supplements like omega-3 fatty acids and glucosamine are often encouraged for optimum joint health.

Lifestyle modification is often helpful to relieve joint stress.  For instance, those who find writing painful may reduce their pain by typing, or using voice control software.  Sufferers of back or hip pain should avoid standing for prolonged periods, and keep their knees slightly bent while standing.  Pay special attention to posture.  Brace support like knee, ankle, or wrist braces can lesson stress, but care is needed when using them.  If you depend on them too much they actually contribute to weaker joints.  Learn what activities are painful, and find ways to avoid them.

More about this author: Alice Shoaf

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