Final answer:
In the context of a medical malpractice lawsuit, when a physician is held liable for a medical assistant's error, it is under the legal doctrine of respondeat superior, which is part of medical malpractice law and relates to the principle of nonmaleficence.
Step-by-step explanation:
When a medical assistant makes a medication error under the physician's direction that results in patient injury, and a court determines that the physician is liable for the medical assistant's negligence, this is known as respondeat superior. This legal doctrine holds that an employer is responsible for the actions of employees performed within the course of their employment.
This principle is one aspect of the wider field of medical malpractice law, which also encompasses the principle of nonmaleficence, stating that healthcare professionals should not cause harm to patients. Physicians are expected to act in ways that minimize the risk of harm and to ensure that any necessary procedures do not result in unnecessary injury to the patient. Cases of liability become complex when considering protocols, equipment failure, and the physician's duty to 'do no harm,' such as in discussions around the ethics of euthanasia.