[IceMan]

Judging by your description of the mechanism of injury the most likely explanation would be a "scapholunate" injury. The scaphoid and the lunate are 2 of the small bones that can be found in the wrist. The scaphoid is situated by the "hollow" at the base of the thumb that you are describing and the lunate is next to that bone closer to the midline of the wrist. Extension of the wrist while it is under a load would certainly stress the scapholunate ligament and if done repetitively could lead to a tearing of the ligament with subsequent instability and even possible dislocation (or dissociation as it is commonly referred to) of the 2 bones.

Instability may not necessarily be picked up on x-ray films but certain clinical tests by a physio skilled in treating wrist and hand conditions or an orthopedic surgeon could shed some light on the issue. If you have a scapholunate dissociation this would be evident on x-ray films. Left untreated this could lead to arthritic changes occurring in the wrist.

The other possibility is that you have a scaphoid fracture but I would think that this is the least likely scenario judging by your description of the cause and onset of pain.

By the way do you have any numbness or tingling in the hand (more specifically the thumb and index finger) or weakness of the thumb and index finger? If any of these signs or symptoms are present it may be suggestive of carpal tunnel syndrome which is caused when the median nerve which passes through the wrist becomes impinged.

I think your best course of action would be to find somebody who has treated wrist conditions and who could do specific tests in the clinic which would be of diagnostic value (these tests are very simple and basically involve pressing on the bones and shifting the one bone in relation to the other - pain, clicking/clunking or excessive movements would indicate a positive test). I think an x-ray would also be of value.

See if you can get somebody to prescribe or fabricate a wrist splint which will prevent excessive hyperextension of the wrist. Gently squeezing a ball or a towel roll will help to stabilize the wrist to an extent and help to rid the wrist of any inflammatory substances. Of course ice and rest would be of benefit to reduce the inflammation as well. Once you see a therapist who can do a detailed examination he/she may suggest more specific exercises which may be of benefit. Ultimately though if you do have a dissociation surgery may be required.

Hope this helps.