rib within a rib sign
A descriptive term for the double contour/parallel lines seen in the ribs on a plain chest film, which is linked to subcortical osteoporosis in patients with severe chronic thalassaemia.
Synonyms Rib-in-a-rib appearance, rib-in-a-rib sign, rib-within-rib sign
Reference Radiol Clin Biol. 1973;42(2):126-33.