Final answer:
The Rhese method, used for visualizing the optic canal, typically involves a 53-degree angle between the median sagittal plane and the IR for optimal imaging of the orbital structures.
Step-by-step explanation:
The parietoorbital projection, often referred to as the Rhese method, is a radiographic technique used to visualize the optic canal, which is an important anatomical feature at the posterior apex of the orbit that allows for the passage of the optic nerve from the retina to the brain. The median sagittal plane is a virtual plane that divides the body or a body part into right and left halves, and in this projection, it would be orthogonal to the image receptor (IR). The specific angle formed between the median sagittal plane and the IR in the Rhese method is typically around 53 degrees to align the orbitomeatal line with the IR, allowing for an optimal view of the optic canal.