If you have not sent anything off yet then the medical form that was given to your husband at the end of the exam goes in with the rest of your application when you send it off to CPC Mississauga. This ensures that when the DMP sends off the full medical report to Mississauga they are able to match it up with your application whatever stage it is at.
They don't send the results to Mississauga. Yes, she includes the receipt of the medical exam with her application papers but this is forwarded to the visa office where the application is processed if she is approved for sponsorship.
saralune, here is where you can find this information:
http://www.cic.gc.ca/english/department/partner/dmp/exam.asp