<prompt> Lower esophageal sphincter lies at what distance from the incisor teeth?15cm25cm40cm50cm  <response>: Ans. is c i.e., 40cm 2nd constriction is at T4 level where arch of aorta crosses esophagus.Esophageal constrictionsNumberDistance from incisorBony levelAnatomical landmark1st15 cm 6 inchesC6At its beginning pharyngo-esophageal junction2nd22.5 cm 9 inchesT4Crossing of aortic arch3rd27.5 cm 11 inchesT6Crossing of left main bronchus4th37.5 - 40 cm 15-16 inchesT10Piercing diaphragm at lower esophageal sphmotor 