A small bone protruding from the back of the foot may be a local bone lesion, such as bone cyst, osteochondroma, or sometimes it may be a soft tissue mass that feels like a bone protruding, such as a tendon sheath cyst, so you can go to the orthopedic department of the hospital to see a doctor in time, and the doctor will make a preliminary judgment whether it is a bony mass by combining with physical examination. The local mass can not be pushed generally belongs to the bony mass, you can improve the local X-ray examination to help determine; the mass can be pushed generally belongs to the soft tissue mass, you can choose ultrasound examination to help determine. According to the examination results, follow-up treatment can be done. Bone cysts, osteochondroma or tendon sheath cysts are generally benign lesions, which can be followed up and observed or can be removed by local surgery.