A hard, cartilage-like lump the size of a grain of rice on the wrist is one of the symptoms of a tendon sheath cyst. Tendon sheath cyst (thecal cyst) is the most common type of mass on the dorsal side of the wrist, and can also occur in other parts of the body on the joint capsule and tendon sheath. Mainly occurs in several groups of people, a class of office workers, every day hand holding the mouse wrist and tiger’s mouth repeated too much force, a class of breastfeeding female friends, post-partum weakness, coupled with the care of the baby, wrist strain caused by tendon sheath inflammation, a class of older women, taking care of children and grandchildren, taking care of the family, the result of exertion. So, how should patients self-diagnose? The following is the diagnostic method of the lump in the wrist that is as hard as cartilage as the size of a grain of rice: 1, general symptoms Tendon sheath cysts can occur at any age, mostly in young and middle-aged, more women than men. The cysts are slow growing, round, and generally not more than 2cm in diameter. there are also those who are found suddenly. In a few cases, the cysts may subside on their own or grow back. In some cases, there is no self-conscious discomfort except for localized swelling, and sometimes there is mild pressure pain. Sometimes there is mild pressure pain. Most cases have localized soreness or discomfort, which affects the activities. 2.Local symptoms When examined, a round mass with smooth shape and clear boundary can be felt, and the surface skin can be pushed without adhesion. Most of the cysts are of high tension, the mass is tough, a few are soft, but all of them are cystic. The roots of the cysts are fixed and there is little movement.Ultrasound can help determine the nature of the mass. Hard cartilaginous masses of the wrist of the size of a grain of rice occur mostly on the dorsal side of the wrist and a few on the palmar side. The best site is at the dorsal wrist joint capsule on the radial side of the tendon of the common extensor digitorum brevis, followed by the radial side between the flexor carpi radialis tendon and the extensor digitorum longus tendon. Tendon sheath cysts on the palmar aspect of the wrist joint sometimes need to be differentiated from radial artery aneurysms by protecting the radial artery, cephalic vein, and superficial branch of the radial nerve when removing the cyst there. Cysts may also occur in the flexor tendon sheath in the carpal tunnel, compressing the median nerve and inducing carpal tunnel syndrome. A few tendon sheath cysts may occur on the tendon sheaths of the flexor muscles of the fingers farther away from the metacarpophalangeal joints, which are the size of a grain of rice and as hard as cartilage.