If a patient has "RUE," which part of the body are we referring to?

The term "RUE" refers specifically to the "Right Upper Extremity," which encompasses the arm, forearm, wrist, and hand on the right side of the body. In medical terminology, "right" indicates the side of the patient's body (which is the opposite of the observer's right), "upper" denotes the section of the limb that is above the elbow, and "extremity" refers to the limbs in general.

The other options correspond to different areas of the body: the right lower extremity would refer to the leg, the right lower quadrant pertains to a region of the abdomen, and the right upper quadrant also specifies a particular abdominal section. Therefore, the terminology highlights the area associated with the upper arm and shoulder region, which makes "B" the correct choice.