M61.5: Other ossification of muscle

Other ossification of muscle refers to a relatively rare musculoskeletal disorder where an abnormal formation of bone, or ossification, occurs within the muscle tissue. This process is generally the outcome of an injury or bruise on the muscle, which then triggers a process within the body which mistakenly replaces muscle with bone. The affected individual often experiences progressive stiffness and loss of mobility in the involved muscle groups, pain, swelling, warmth or redness over the affected area, and potentially decreased range of motion. The condition has the potential to limit physical activity drastically if it involves large muscle groups. Untreated, it can eventually lead to significant deformity and disability. As the disease progresses, it severely affects the person's quality of life.