General surgery is a discipline of surgery having a central core of knowledge common to all surgical specialties–anatomy, physiology, metabolism, immunology, nutrition, pathology, wound healing, shock and resuscitation, intensive care, and neoplasia. General surgeons are trained to manage a broad spectrum of diseases and injuries affecting almost any area of the body that requires surgical intervention. These physicians are involved in diagnosis, preoperative, operative and postoperative care of the surgical patient, and they are trained to provide comprehensive management of trauma and complete care of critically ill patients with underlying surgical conditions. The surgeon uses a variety of diagnostic techniques, including endoscopy, for observing internal structures, and may use specialized instruments during operative procedures. Although its scope is broad, general surgery usually involves the abdomen, breasts, peripheral vasculature, skin, and neck.