<prompt> Constrictions of the esophagus are present in all sites exceptAt cricopharyngeal junctionCrossed by Arch of AoaSurrounded by Right crus of DiaphramCrossed by left principle bronchus  <response>: ConstrictionsNormally the esophagus shows 4 constrictions at the following levels.1.At its beginning, 15 cm from the incisor teeth.2.Where it is crossed by the aoic arch, 22.5 cm from the incisor teeth.3.Where it is crossed by the left bronchus, 27.5 cm from the incisor teeth.4.Where it pierces the diaphragm 37.5 cm from the incisor teethRef: BD Chaurasia; Volume 1; 6th edition; Page no: 268 