A histological observation on the flexor tendon healing within intact sheath.

In this study we allowed the sutured chicken flexor tendons to glide back into the uninjured sheaths in order to keep the healing process of flexor tendon from being affected by the healing of surrounding wounded tissues. By observing 12 chickens, 72 digits, with light microscope and transmission electron microscope, it was found that the visceral and parietal synovium of the sheath were the regions with earliest and most active cell proliferation and the major source of repairing cells during the healing process of the flexor tendon. Tendon cells had the ability of intrinsic healing, but delayed as compared to synovium cells. Adhesion between intact parietal synovium and healing tendon and its surrounding tissue could not be avoided.