Location of First constriction of esophagus from the incisor tooth:

Ans. (a) 15cmBailey and Love 26th ed. ch. 621982The esophagus has 3 constrictions in its vertical course, as follows:* The first constriction is at 15 cm from the upper incisor teeth, where the esophagus commences at the cricopharyngeal sphincter; this is the narrowest portion of the esophagus and approximately corresponds to the sixth cervical vertebra* The second constriction is at 25 cm from the upper incisor teeth, where it is crossed by the aortic arch and left main bronchus.* The third constriction is at 40 cm from the upper incisor teeth, where it pierces the diaphragm; the lower esophageal sphincter (LES) is situated at this level.