The answer is yes, no and maybe.
Yes if your case is pending in Maryland Circuit Court or U.S. District Court and the " mental or physical condition of a party is in controversy and for good cause shown."
Which is to say in car or truck accident case, the defense can request an examination by a doctor of their choosing and often do. They can't just compel it absent a court order. To be clear the courts almost always compel the injured plaintiff to attend such an examination unless it is with an inconvenient doctor or one that is not calculated to lead to an admissible medical opinion. In which case it is maybe.
No, if the case is in Maryland State District Court where the rules make no provision for such an examination.