constrictions
Last reviewed 01/2018
Behind the appendix, the oesophagus is the second most narrow section of the gastrointestinal tract. To further complicate the interpretation of barium swallow images or the passage of endoscopes and tubes, the oesophagus also has a number of constrictions - regions of narrowing evident on distention:
- 15cm from the incisor teeth; caused by pressure from cricopharyngeus
- 22cm from incisors; caused by extramural passage of aortic arch
- 27cm from incisors; caused by extramural passage of left principal bronchus
- 38cm from incisors; caused by extramural pressure from diaphragmatic crura
Rarely, an enlarged left atrium may cause a constriction; conversely, gastrointestinal endoscopy combined with ultrasonography has been used to image the heart.
The sites of constriction are also commonly the points at which large or irregular foreign bodies impact during descent through the lumen.