The following are links to sites that I find helpful in the realm of hand-based occupational therapy!
Washington University in St. Louis - School of Medicine Program in Occupational Therapy

As of 2008, the #1 school for occupational therapy in the nation and, I'm proud to say, where I was given my OT education!
University of Washington’s Muscle Atlas

Amazing graphics of individual muscles of both the upper and lower extremity. Other pertinent information supplied by this site are muscle origins, insertions, innervations, and vascular supplies.
www.e-hand.com

Paragraph.
American Occupational Therapy Association

Paragraph.