Medically means 'when we look at this the way medicine looks at it' — doctors, disease, injury, treatment. If a test or an operation is medically necessary, a doctor says you need it for your health, not only because you would like it. If someone is medically unfit, their body is not well enough for a job, a flight, or a sport. People also say medically speaking when they want to separate the doctor's view from money, law, or feelings: medically speaking the patient is stable, but they are still frightened. It is an adverb: it tells you from which angle. You will see it in hospital letters, insurance fights, and news about public health. Though actually, students often treat it like the adjective medical. We say a medical problem, a medical student; we say the wound was treated medically, or the claim is not medically justified.