Surgery and Emergency Medicine are separate rotations....
Surgery is typically a required 3rd year rotation, and your level of activity is highly dependent on the attending physician you are with. A typical general surgery rotation usually consists of 3-4 days in the operating room/week, 1-2 days of clinic/week, and taking overnight call every 3rd or 4th night. Depending on which service you are on, you could see craniotomies (neurosurg), exploratory laparotomies (trauma), facial reconstructions or breast reductions (plastics), bowel resections (colorectal or general), or open-heart surgery/CABG (CT). Students usually follow a couple patients on the floor, and retract in the operating room with an occational closure or assist on the case. If you are lucky, the surgeon/residents will let you make some incisions or help with the resections. On the floors, you may get to do procedures such as central line insertion, arterial line placement, chest tube insertion, suturing, or irrigation and debridements. Students are generally not very involved in decision-making for the patients on a surgery rotation.
Emergency Medicine is usually a 4th year rotation or an elective. You typically see patients in the department and are expected to move quickly and efficiently. The main goal is diagnosis and then disposition. Your attending supervision can range from little-to-none (county hospitals), to very strict (affluent suburban hospitals). In general, emergency departments are very over-worked, so a students help is very welcome. You come up with the plan-of-care for the patient, and the attending will confirm and/or revise it. At times you may be the only person to really see the patient. Typical procedures a student may encounter on Emergency Medicine would include IV placement, lots of suturing, irrigation and debridements, central line placement, chest tube insertion, intubation, and CPR. You also become familiar with participation in initial trauma managment. Emergency medicine physicians do NOT operate.