Bare orbit sign is a feature of

Bare Orbit sign is seen in cases of NF-1 and is due to sphenoid Dysplasia especially Greater wing of sphenoid, with Absent innominate line on frontal skull radiograph NF1 is associated with some characteristic bone dysplasias, including lambdoid sutural dysplasia, thinning of long bone coices and kyphoscoliosis with a high thoracic acute curve. One of the most common is sphenoid wing dysplasia marked by a bone defect which allows herniation of the temporal lobe through the orbit. On plain radiography, this produces the 'empty' or 'bare' orbit.