ABSTRACT
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis and manifested by formation of tubercles and caseous necrosis in tissues. In the musculoskeletal system, tuberculous spondylitis is the most typical form of the disease; however, joint changes in extraspinal sites, such as the hip, knee, wrist and elbow, also may occur. Other abnormalities commonly encountered are tuberculous dactylitis and involvement of the tendon sheath. Characteristically, the tissues respond to the mycobacterial infection by forming tubercles. Clusters of epithelial cells surround a central zone of caseating necrosis, with the central part of the tubercle being composed of multinucleated giant cells and the periphery consisting of a mantle of lymphocytes. Special types of tuberculous osteomyelitis include cystic tuberculosis and tuberculous dactylitis. The radiographic characteristics of cystic tuberculosis resemble those of eosinophilic granuloma, sarcoidosis, cystic angiomatosis, plasma cell myeloma, fungal infections, metastases and other conditions. Tuberculous dactylitis involving the short tubular bones of the hands and feet occurs especially frequently in children. In addition to soft tissue swelling, periostitis of phalanges, metacarpals or metatarsals may be evident. Expansion of the bone with cystic quality is termed spina ventosa.Tuberculosis of the metacarpals ,metatarsals and phalanges is uncommon after the age of five years.