My thigh used to do that. In my case, it was episodic, probably linked to stress or dehydration from drinking.

Seems to match description of Hyperkinetic Movement Disorder at University of Michigan Healoth System. Tardive Dyskinesia / Philip, do these problems match the description of Hyperkinetic Movement Disorder at the University of Michigan Health System ?
http://www.med.umich.edu/md/patient/conditions-hyper.htm

Tardive Dyskinesia / Tardive Dystonia
"Tardive dyskinesia or tardive dystonia, both referred to as "TD," refers to a wide variety of involuntary sterotypical movements caused by the prolonged use of dopamine receptor-blocking agents. The most common dopamine receptor-blocking agents are antipsychotics and anti-nausea agents. The classic form of TD refers to stereotypic movements of the mouth, where patients look like they are chewing gum. However, TD can take the form of other involuntary movements such as chorea, dystonia or tics."

Nutritional treatment of TD is here
http://www.alternativementalhealth.com/articles/td.htm

http://pharmaceuticalsanonymous.blogspot.com/2008/03/nutritional-treatment-of-tardive.html

Prevention of TD - see pdf here:
http://orthomolecular.org/library/jom/1981/pdf/1981-v10n02-p119.pdf

look up fasiculations. There are some hand examples on youtube.

you mean there's sensible information on the Net? hehehehe

Muscle cramps, usually caused by sports or occupational muscle injury

Parkinson's disease

Hypocalcemia (low calcium levels in the blood)

Hypermagnesemia (high magnesium levels in the blood)

Thyroid disorders

Dystonia

Huntington's disease

Hyperventilation -- calcium becomes temporarily unavailable to the body during hyperventilation

Damage to a single nerve or nerve group (mononeuropathy) or multiple nerves (polyneuropathy)

Multiple sclerosis

Various medications

http://www.umm.edu/ency/article/003194.htm

Maybe it's the previous Seroquel use, anyway the good news is, you can scratch your head so all is well! :)

Philip,
Are you right-handed? If so, maybe you need an ergonomic mouse:
http://www.thehumansolution.com/quillmouse.html

Being 12yrs + on Seroxat has left me with tremors jerky movements ,and the spasms you talk about.

You were on Seroquel for a time, weren't you? Could this be a delayed side effect? Seroquel's known for TD and other movement disorders.

I also ask "Are you right-handed?".
I think I have had similar . I think it is a mild form of carpal tunnel syndrome.
Constant use of the right hand when using the internet.
Solution?
Switch to the left hand from time to time.

I wouldn't call what I've had 'spasms,' exactly -- mine have been more like 'tremors.' In precisely that area of soft tissue that can be pinched by the thumb and forefinger of the other hand.

I'm 62 and in pretty good general health, calcium and potassium levels generally within normal limits.

Every time I've had these tremors in the right hand's space between thumb and forefinger it has followed a long period of mousing -- browsing the web and following the 'click-here' trail, or editing a document and repeatedly clicking to highlight a paragraph and change its format.

I've had some relief just from switching back and forth between two mice, one a touch-pad with clickers that are pressed DOWN by the THUMB, and the other a trackball with clickers that are pressed DOWN by the index and middle fingers.

After all the expertise available on fs, I need never go to a doc again. Electronic medicine, here we come!!!

Philip,
Please check with a doctor.
You will receive so many ideas from all of us that it will make you more and more confused.
Hope you get better.

Ignore it. I'm a doctor, and if you presented to me with that, and had no residual symptoms, and it wasn't happening with increasing frequency, I'd say don't worry about it.

If it's happening often, or getting worse, or you have other symptoms associated with it (symptoms other than occasional fasiculations), I'd suggest you visit your doc. It's still likely to be nothing.

Common things are common. And idiopathic fasiculations are common. Most other things that cause intermittent fasiculations are uncommon.

Chill.

J

there is an old saying amongst s x therapists...

switch to the left hand.

:)