The role of Surgeon was an extremely important one in the Civil War regiments. The 9th Ky had by all evidence a very good Surgeon named Dr. Jeffreys who served the whole time along with several assistants. His records show he spent a lot of time detached to Brigade Surgeon, so he must have been known in the Brigades as one of the better Surgeons. The Surgeon was responsible for the health and well-being of the men and officers under his control and he answered to nobody in his Regiment in matters of health. In fact, he is mentioned in a few records of service pages of the men, as well as Marcus Woodcock's memoir in such a way that show he was respected, but also may have been a bit of a stern man.
Today's Surgeon role is filled by Maj. Dave Brunner who has built up an impressive display of medical instruments to show visitors. He can deliver talks to explain the techniques Surgeons used to treat illness or wounds and explain the reasons for so many horrific casualties.
During battles he is on the field in case of real medical emergencies and checks on the fallen to make sure they are pretending and not really having a medical issue. He has had assistants help him in this as well.