Which type of consent involves a patient being lucid and of legal age?

The correct choice is expressed consent. This type of consent is obtained when a patient voluntarily agrees to a medical intervention after being fully informed about the procedure, its risks, and benefits. For consent to be considered expressed, the patient must be of legal age and possess the mental capacity to understand the information provided, allowing them to make an informed decision about their treatment.

Expressed consent is crucial in ensuring that patients have the right to govern their own healthcare decisions. It signifies a clear and affirmative agreement, as opposed to implied consent, which can be assumed in certain emergency situations when a patient is unable to give direct consent. It is also distinct from informed consent, which emphasizes the provision of information regarding risks and alternatives, and is often a more comprehensive process. In contrast, involuntary consent does not involve the patient's willingness, as it is usually imposed due to psychiatric emergencies or legal directives.

Understanding the nuances of expressed consent is essential for healthcare providers, as it protects patient autonomy and ensures ethical practice in medical care.