Bilateral optic nerve hypoplasia. a. Coronal T2 magnetic resonance imaging (MRI) of a patient with bilateral optic nerve hypoplasia. The optic nerves are the tiny gray areas within the brighter, cerebrospinal fluid-filled optic nerve sheaths. b. Axial T2 MRI of the same patient with an absent septum pellucidum. (The septum pellucidum is a thin septae located in the midline of the brain, between the 2 cerebral hemispheres, normally in the location of the arrow.) c. Saggital T1 MRI demonstrating the presence of an ectopic pituitary bright spot (circled), and the absence of the posterior pituitary bright spot (should be in location of arrowhead).