General surgery is a subspecialty of surgery that focuses on abdominal contents such as the oesophagus, stomach, small intestine, large intestine, liver, pancreas, gallbladder, appendix, and bile ducts, and often the thyroid gland as well. They also treat disorders that affect the skin, breast, and soft tissues, as well as trauma, peripheral artery disease, and hernias, and they do endoscopic procedures such as gastroscopy and colonoscopy.