The term heterotopic ossification denotes new bone formation in tissues which do not nor­mally ossify. Fibrous tissue and striated muscles are the most commonly involved. Heterotopic ossification often develops after local tissue injuries (traumatic, surgical, thermal) and/or cen­tral nervous system injuries. The anatomical sites most often affected are: hip, knee, elbow and shoulder. In most cases, heterotopic ossification is asymptomatic, but it may cause pain and limit the range of motion. Generally, an accurate diagnosis can be established by plain radiography. Two modes of prevention of heterotopic ossification have been shown to be effec­tive: the use of non-steroidal antiinflammatory drugs and local low-dose radiation. Surgical excision of heterotopic bone is indicated when the function of the involved joint is signifi­cantly diminished. Since there is a great possibility of reoccurrence, surgical treatment of heterotopic ossification should be delayed until heterotopic bone becomes mature, and pre­ventative measures should be introduced immediately after surgery.