May Be Caused by

 Common

Ankylosing spondylitis

Degenerative changes

Healed osteitis pubis

Healed osteomyelitis

Idiopathic pubic fusion

Osteoarthritis

Parturition

Trauma

 Uncommon

Alkaptonuria

Fluorosis

Juvenile chronic arthritis

Juvenile rheumatoid arthritis

Myositis ossificans

Psoriatic arthritis

Radiation therapy

Rheumatoid arthritis

Sternocostoclavicular hyperostosis

Surgical fusion