<unk>  refers to the biconcave appearance of the<unk>  in sagittal radiographs due to pathological changes, such as demineralisation.<unk>  appearance of the<unk>  is seen in several conditions such as osteoporosis, steroid or heparin therapy, Cushing syndrome, idiopathic, sickle cell disease, leukemia, Duchenne muscular dystrophy, and homo-cystinuria.<unk>  sign is usually first seen in lumbar<unk> e.
Codfish vertebra
Sesamoid bone
Cradle cap
Tophus
Tram track 
Phrygian cap 
Frenulum breve
Choroid