<prompt> Constrictions of esophagus when measured from upper incisors are present at15cm, 20cm, 40cm15cm, 25cm, 40cm20cm, 30cm, 40 cm30cm, 40cm, 60 cm  <response>: At- 15 cm 6 inch from incisor at cricophyrangeal junction behind the cricoid cailage At 25 cm Broncho-aoic constriction2328?502?25cm At 40 cm15 inch from incisor -esophageal hiatus where it passes through the diaphragm in the posterior mediastinumT10 At 23 cm9 inch from incisor -due to crossing of arch of aoa in front in the superior mediastinum At 28 cm 11 inchfrom incisor -esophagus is compressed by the left main bronchus in the posterior mediastinum 