The rectum is the part of the gastrointestinal tract that continues from the sigmoid colon of the large intestine to the anal canal and has a thick muscular layer. It follows the curvature of the sacrum and is firmly attached to it by connective tissue. The rectum is about 12 centimeters long and ends about 5 centimeters below the tip of the coccyx, at the beginning of the anal canal. Feces is stored in the rectum before being expelled along the anal canal.