The field of hand surgery deals with both surgical and non-surgical treatment of conditions and problems that may take place in the hand or upper extremity (commonly from the tip of the hand to the shoulder). Hand surgery may be practiced by graduates of general surgery, orthopedic surgery and plastic surgery. Plastic surgeons and orthopedic surgeons receive significant training in hand surgery during their residency training, with some graduates continuing on to do an additional one year hand fellowship. These fellowships are sometimes also pursued by general surgeons. Plastic surgeons are particularly well suited to handle traumatic hand and digit amputations that require a "replant" operation. Plastic surgeons are trained to reconstruct all aspects to salvage the appendage: blood vessels, nerves, tendons, muscle, bone. Orthopedic surgeons are particularly well suited to handle complex fractures of the hand and injuries to the carpal bones that alter the mechanics of the wrist. Hand surgeons perform a wide variety of operations such as fracture repairs, nerve decompressions, releases, transfer and repairs of tendons and reconstruction of injuries, rheumatoid deformities and congenital defects.

From http://en.wikipedia.org/wiki/Hand_surgery