Which of the following is not part of the inner-to-outer retina sequence listed?

• A. Inner Plexiform Layer
• B. Outer Nuclear Layer
• C. Bruchs Membrane
• D. Rods and Cones

Answer: (C)

Understanding the layering of the retina from the inner surface toward the choroid helps distinguish which components are true retinal layers versus boundary structures outside the retina.

The inner plexiform layer and the outer nuclear layer are both definite retinal layers: the inner plexiform layer is where synapses between bipolar, amacrine, and ganglion cells occur, while the outer nuclear layer houses the cell bodies of the photoreceptors. Rods and cones are the photoreceptor cells themselves, localized in the outer retina, and their outer segments extend toward the retinal pigment epithelium.

Bruch's membrane, however, sits just outside the retina, between the retinal pigment epithelium and the choroid. It is a support membrane at the interface with the choroid, not a layer of the retinal tissue itself. For that reason, it is not considered part of the inner-to-outer retinal sequence.