What is defensive medicine?
Defensive medicine is the situation in which a doctor practices medicine, either through diagnosis or treatment, not to help the patient, but rather to prevent legal action (a malpractice suit) if a problem occurs. The doctor goes beyond what is usually necessary for diagnosing and treating the patient so they can ensure they are not missing any unlikely but possible condition.
They may perform procedures that the patient wants or expects even if they aren't clinically necessary, to keep the patient satisfied. For these reasons, defensive medicine is said to lead to overtesting and overtreatment. They want to prevent bad outcomes (however unlikely) and to prevent having an angry patient.