The term of the abdomen refers to the area of the body located between the chest and the pelvis. Celiac and Coeliac are two different spellings for the same condition, which is an autoimmune disorder that affects the digestive system. People with this condition have difficulty digesting gluten, a protein found in wheat, barley, and rye. Symptoms can include abdominal pain, bloating, diarrhea, and weight loss. Treatment typically involves following a gluten-free diet.