The lower end of the oesophagus.

The lower end of the oesophagus is a region where the pathology, the physiology, and even the anatomy are not quite clear. This paper attempts to dispel some of the confusion. WHERE IS THE OESOPHAGO-GASTRIC JUNCTION ? The oesophagus or gullet is the tube which conducts food from the throat to the stomach, and the stomach is the pouch in which food collects and undergoes the initial stages of digestion and absorption. These simple definitions may seem so obvious as to be hardly worthy of mention, but they are fundamental. From the outside it is easy to see where the tube ends and the pouch begins. As well as the abrupt change in shape there is the peritoneal reflection from stomach to diaphragm to mark the junction. It is therefore a definite, easily identified, anatomical region and will be referred to in this paper as the oesophago-gastric junction. From the inside the only line of demarcation apparent is the wavy line of junction of stratified squamous with columnar epithelium; but it is not at the level of the oesophago-gastric junction as defined above. It is 1 or 2 cm. higher. In longitudinal sections there is no sudden change in the macroscopic or microscopic appearance of the muscle coat or the submucosa at the oesophago-gastric junction, and the columnar epithelium also passes without change across the junction into the stomach for a centimetre or two before it gradually alters to gastric epithelium of fundal type. Under the microscope the oesophago-gastric junction cannot be identified, so it is not surprising that histologists adopted the only line of demarcation available to them, namely the sudden change from squamous to columnar epithelium, and called the squamous epithelium oesophageal and the columnar epithelium gastric. Hence we have all been taught that the oesophagus is a tube lined by squamous epithelium. This has put us in the ridiculous position of having the oesophago-gastric junction at a different level according to whether the tube is viewed from inside or outside. I firmly believe that this anomaly should be corrected and that the only way to correct it is to go back to the simple definition given above. The oesophagus is a tube and all of this tube is oesophagus, regardless of its lining. The true junction is where the conducting tube changes to the digesting pouch. This means that the oesophagus is not lined exclusively by squamous …