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Injuries and Conditions > De Quervain Syndrome          
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De Quervain Syndrome
(aka De Quervain's Tenosynovitis, Radial Styloid Tenosynovitis, Blackberry Thumb)

What is De Quervain Syndrome? Top
              View of Hand

De Quervain Syndrome is an inflammation of the two tendons which provide articulation of the thumb.  The tendon moves inside a synovial sheath which when inflamed thickens and swells, restricting the movement of the tendon and can lead to the formation of painful cysts.

Both the extensor pollicus brevis and the abductor pollicus longus tendons are employed to move the thumb away from the hand in the same plane as the palm (i.e. 2-dimensional movement, or radial abduction).  Other tendons move the thumb away from the palm of the hand (palmar abduction) and are not affected by this Syndrome.

What are the Symptoms of De Quervain Syndrome?

Common symptoms include pain and swelling in the 'thumb side' of the wrist and a noticeable reduction in the ability to grip  The pain can also radiate up from the wrist to the thumb and down through the forearm, and worsens with use of the thumb or hand.  Any forceful pinching, twisting, gripping or grabbing actions will heighten the pain.  Sometimes a reduced range of motion of the thumb will also occur.  A 'snapping' sensation when the thumb is moved indicates the presence of a cyst which the tendons are moving over. 

Finklestein's Test

This test is used to diagnose De Quervain Syndrome.  To perform this test, make a fist with the thumb under the fingers.  Then bend the wrist away from the thumb side of the hand, towards the little finger side of the hand.  For most individuals this test is mildly painful, but for individuals suffering from De Quervain Syndrome it is very painful.


What Causes De Quervain Syndrome to Develop?

There is no clear consensus in the scientific community as to the clear cause of De Quervain's Tenosynovitis.

The leading theories attribute the most likely cause to repetitive movements of the thumb, especially when the thumb is moved in a posture with significant abduction and extension.  Examples of this are thumb based trackballs, and generating text with a cell phone (which has led to some calling this syndrome "Blackberry Thumb").

Another cause is theorized to arise from performing repetitive actions with the hands that require sideways movement of the wrist while gripping the thumb (i.e. mousing with some mice). 

The syndrome occurs most frequently in individuals who are between 30 and 50 years of age and is significantly more common in women than men.  Part of the reason for this gender disparity is that is not uncommon to occur during and after pregnancy.

What Movements Should be Avoided if you have De Quervain Syndrome?

Any lateral movement of the thumb relative to the hand or actions requiring the need to grip with the thumb.  Most conventional mice require a Static Grip Force which uses the tendons affected by De Quervain's Syndrome.  Any pointing device which requires movement of the thumb to perform mousing actions (i.e. thumb based trackballs, or using a thumb button on a mouse or touchpad) could also represent movements you would want to avoid.

What Types of Products can be Used to Help Prevent or Reduce the Symptoms and Incidence of De Quervain Syndrome?

Orthopedic Mice of the correct size for the user which properly support the structure of the hand and minimize or eliminate the need to exert Static Grip Force will be of significant benefit.  Touchpads, Trackballs and Central Pointing Devices will eliminate the need to grip the mouse, and when used properly will not require undesired thumb movement.


Last edited December 16th, 2013

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