Final answer:
The bones in which marrow is exposed when the operator is wearing a leaded apron and facing the patient are the arms.
Step-by-step explanation:
Bones with Exposed Marrow when Wearing a Leaded Apron
The bones in which marrow is exposed when the operator is wearing a leaded apron and facing the patient are the arms. When the operator is taking an x-ray, the arms are typically positioned outside of the apron, exposing the bone marrow to any scattered radiation.
It is important for the operator to take necessary precautions and minimize exposure to radiation by standing behind a lead-lined door with a lead glass window.