Hand joints protrude a bone, the common reasons are the following: 1, due to bone degeneration, hyperplasia or a variety of arthritis end performance, resulting in the appearance of osteoarthritis of the finger joints, the appearance of bone growth, deformation, destruction of articular cartilage, joint enlargement and a series of symptoms, due to bone growth, will be manifested as a protruding piece of bone. 2, seen in the finger joints have suffered a trauma, not After systematic treatment, local deformity healing will result in deformation of the bone, which will also have to protrude a bone. 3, some times the protrusion is not necessarily bone, but just a hard swelling to the touch, often also seen in tendon sheath cysts. Tendon sheath cysts after a long period of extrusion as well as absorption of water, there will be a hardening of the cyst, touching like a bone, but it is actually a cyst. Patients are advised to go to the hospital for a detailed examination and a definitive diagnosis through x-rays and ultrasound.