If you cut the tendon of your middle finger with glass, it is recommended that you stop the bleeding first, fix it with a simple bandage and do not move your knuckle excessively. Go to the hospital as soon as possible to avoid complications such as joint stiffness and deformation of the hand in the future. Tendons are the so-called tendons, and there are extensor tendons and flexor tendons in the fingers. Flexor tendon injury refers to the tearing or severing of the tendon on the palm side of the hand, which will result in the inability to bend the fingers; while extensor tendon injury refers to the tearing or severing of the tendon on the back side of the hand, which will result in the inability to straighten the fingers. Tendon repair surgery is generally recommended for both flexor and extensor tendon injuries. Timely and appropriate post-surgical hand rehabilitation is important for the prognosis of hand function. The main goal of hand rehabilitation is to immobilize the wrist and fingers in a flexed or straightened position. Protective casts or splints are needed to keep the tendons in the most relaxed condition and to obtain better repair and tendon tone.