What is the central ray's relationship to the skin surface when positioning for a TAN projection?

In mammography, particularly for the Tangential (TAN) projection, the positioning of the central ray is crucial for obtaining the correct images of the breast tissue. In this projection, the central ray is directed parallel to the skin surface, which allows for the visualization of superficial lesions or conditions that may not be well seen with more standard projections.

By positioning the central ray parallel to the skin, the X-ray beam is able to achieve optimal imaging of the skin line and the underlying pathology while minimizing the amount of tissue distorted or obscured by standard perpendicular angling. This technique is especially important in assessing areas close to the skin, such as skin lesions or other superficial abnormalities that require a clear image to aid in diagnosis.

Thus, the correct answer emphasizes the need for parallel alignment with the skin surface to achieve the intended diagnostic outcome in a TAN projection.