Final answer:
To avoid self-injury when lifting, the nurse should keep the back straight and bend at the knees, utilizing leg muscles instead of the weaker spine.
Step-by-step explanation:
The nurse should prevent self-injury while lifting the bedside cabinet by keeping her back straight and bending the knees. This leverages the leg muscles, which are more robust and better suited for lifting, as opposed to the spine which is relatively weak. Lifting with the back can apply excessive force on the spine, potentially causing injury. Therefore, the correct action to take when lifting to prevent self-injury is to keep the back straight and bend at the knees.