J-shaped sella sign

The J-shaped sella sign is a radiologic sign observed on lateral views of skull radiographs as the forward elongation of the sella turcica, and its extension below the anterior clinoid process.^[1] This abnormality causes the sella turcica to resemble the letter J. This sign is a normal variant in 5% of children,^[1] but it is also associated with optic nerve glioma, hydrocephalus, mucopolysaccharidoses, and achondroplasia.^[2]