It is a common deformity of the skeletal development of the foot and belongs to the anatomical variant of the navicular bone, located at the medial-posterior border of the navicular bone, with more bilateral onset and partly accompanied by flatfoot deformity. Etiology: In lower animals, the occurrence of paravicular bone is relatively high, and with the evolution of animals, the occurrence of paravicular bone gradually decreases, and it is currently believed that the formation of paravicular bone is due to the abnormal development of the secondary ossification center of the navicular tuberosity. Pathology: An independent ossification center appears on the medial posterior side of the navicular bone, and with age, local ossification and calcification occur, forming an independent paravicular bone. According to the different connection between the paracone and the navicular bone, there are three types Type I, the paracone exists independently without any adhesion to the navicular bone and the circumference is smooth, also called independent seed bone; Type II, the paracone is combined with the navicular bone through cartilage and can form an articular surface; Type III, the paracone is attached to the navicular bone through bone and the articular surface disappears and becomes part of the navicular bone. At the same time, the stop point of posterior tibial tendon is abnormal, and the stop point that should normally be attached to the navicular bone and cuneiform bone is partly in the paracone, which leads to the weakening of the strength of the posterior tibial muscle, and if there is long-term friction, posterior tibial myositis and local bursitis appear, and at the same time, medial arch decline and flatfoot deformity may appear. Clinical manifestations: Generally, there are no obvious clinical symptoms, but there may be bilateral flatfoot with localized bony elevation on the medial side of both feet, without pressure pain, and with increased activity or friction, local pain, redness and swelling may appear. Imaging manifestations: the diagnosis is clarified by X-ray examination. A separate calcified shadow can be seen on the medial posterior side of the navicular bone, with mostly smooth edges and irregular shape, and very rarely fused with the navicular bone. Treatment and prognosis: Generally, conservative treatment is mostly used for the first attack or for those with mild local symptoms. This includes local physiotherapy, wearing loose shoes, hormone closure, etc. At the same time, orthopedic shoes can be used to treat flat feet. For intractable pain, surgical treatment can be used. The main purpose of surgery is to remove the pars plana, while reconstructing the posterior tibial muscle stops and tightening the ligaments. Postoperative deformity orthopedic shoes treatment.