A medical examination to verify good health and admissibility to the U.S. is known as an Immigration Physical. This doctor's exam is used to identify potential medical conditions that would require follow-up medical care after emigration to the U.S. In other cases this might call for an Adjustment of Status to permanent residence.
Unlike a regular physical exam or check-up in which you bring up health issues that you are experiencing, then get a range of medical advice it is more of a screening exam. This examination is to determine whether it is safe to allow you into the United States.