A small bone protrusion on the clavicle may be caused by the following reasons: 1. normal bony protrusion, the clavicle is very close to the body surface, so the normal bony protrusion looks very obvious on the body surface, for example, at the acromion end of the clavicle and the sternum end, there is a corresponding protrusion itself, and will form a joint with the corresponding bone, on the body surface, these two parts have a similar small bone protrusion. 2. Osteomalacia, often seen in patients with previous clavicle fractures, may produce excessive osteomalacia at the fracture end during the recovery process, leading to abnormal bony protrusions. 3. Occupational diseases, such as bone tumors in the clavicle, may cause this symptom. 4. Soft tissue calcification, such as severe contusions in the soft tissue around the clavicle, may occur during the recovery process. abnormal calcium salt deposition may occur, which in turn leads to a relatively hard bony protrusion in this area.