Many years ago, a "surgeon" was a specialist physician who performed operations on every part of the body. However, as surgical technique grew more complicated and standards for excellence and safety more demanding, it became clear that a "specialist" who specializes in everything specializes in nothing.
What emerged out of necessity was the rich selection of surgical specialties we enjoy today, including neurosurgery, cardiovascular surgery, orthopedic surgery, and so on, in which a true expert surgeon can focus his practice around what he or she does the best.
More recently, the field of plastic surgery has undergone a similar evolution as it has grown more difficult for any one practitioner to acquire the knowledge, skills, and experience needed to operate effectively on multiple parts of the body . . .