The esophagus has four constrictions.Where the pharynx joins the upper end - 15 cm from incisor teethThe second is at the where the aoic arch - 22.5 cm from incisor teethThe left bronchus cross its anterior surface - 27.5 cm from incisor teethWhere the esophagus passes through the diaphragm into the stomach - 37.5 cm from incisor teeth These constrictions are of considerable clinical impoance because they are sites where swallowed foreign bodies can lodge or through which it may be difficult to pass an esophagoscope.Because a slight delay in the passage of food or fluid occurs at these levels, strictures develop here after the drinking of caustic fluids. Those constrictions are also the common sites of carcinoma of the esophagus.