The sign marked by the arrows pointing to the ribs, in the below chest X-ray, is diagnostic of which of the following conditions?

Ans. C. Coarctation of aortaThe above chest X-ray shows, inferior rib notching (Roesler sign), which is characteristically seen in patients with coarctation of aorta.Aortic coarctation, or Coarctation of aorta is a congenital condition whereby the aorta is narrow, usually in the area where the ductus arteriosus (ligamentum arteriosum after regression) inserts. Three important findings are:* Inferior rib notching* Figure 3 sign of the aorta* Prominence of the ascending aortaInferior rib notching (Roesler sign): The most common cause is coarctation of aorta, however certain other conditions as follows may cause inferior rib notching:* Takayasu disease* Blalock-taussig shunt* Arteriovenous malformation* SVC obstruction* Certain neurogenic tumors like schwannomaBoth superior and inferior rib notching may be seen in:* Hyperparathyroidism* Neurofibromatosis type 1