The distance of aoic constriction of the oesophagus from the upper incisor teeth
First constriction, at the pharyngo-esophageal junction, 9 cm (6 inches) from the incisor teeth. Second constriction, where it's crossed by the arch of aoa, 22.5 cm (9 inches) from the incisor teeth. Third constriction, where it's crossed by the left principal bronchus, 27.5 cm (11 inches) from the incisor teeth. Fouh constriction, where it pierces the diaphragm, 40 cm (15 inches) from the incisor teeth. Ref - sciencedirect.com
15 cm
22.5 cm
27.5 cm
40 cm
Head and neck