Keep your eyes on the ribs: the spectrum of normal variants and diseases that involve the ribs

A variety of normal variants or pathologic conditions of the ribs may be overlooked at chest radiography if the ribs are not evaluated carefully. Rib lesions may simulate pulmonary disease as well. Normal rib variants include cervical, intrathoracic, and pelvic ribs; forked rib; fusion and bridging; and pseudarthrosis of the first rib. Trauma-related lesions are common and usually occur in isolation but can alert the radiologist to other injuries. Metastases may appear as vague areas of increased opacity overlying the lung if seen en face and typically have a smooth interface with the lung on oblique images. Chondroid lesions nearly always arise at or near the anterior end of the rib. Osteochondroma (exostosis) typically manifests as a deformity or expansion of the rib with calcification of the cartilaginous cap. Acute rib infections are seen as focal areas of bone destruction, whereas chronic infections may manifest as periosteal reaction or a bone sequestrum. Inferior rib notching may be seen in a wide variety of pathologic conditions. Rib abnormalities may also be seen in fibrous dysplasia, Langerhans cell histiocytosis, Paget disease, and various hemoglobinopathies. In most cases, radiography is sufficient for the identification and diagnosis of normal variants and pathologic conditions of the ribs.