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Abstract
The oesophagus is a muscular tube which connects the pharynx to the stomach. Classical anatomy divides the oesophagus into three parts: Cervical, Thoracic, and Abdominal. For the clinician, this view is unserviceable and has led to other perspectives. Function divides the oesophagus according to its differing forms of motility into the following three zones: Upper oesophageal sphincter (UES), oesophageal body, Lower oesophageal sphincter (LES). Surgeons can benefit from viewing the oesophagus as a two-part structure divided into proximal and distal segments bordering at the tracheal bifurcation. This approach best matches surgical needs and therapeutic strategies.
The oesophagus is normally lined by a pale-pink, smooth, and flat mucosa. This mucosa is a non keratinized, stratified squamous epithelium. While advancing the endoscope down the length of the oesophagus, observe the peristaltic activity and distensibility.
There are several key landmarks in the oesophagus:
•The cricopharyngeal sphincter.
•Indentation from the left main bronchus.
•Pulsation of the left atrium and aorta.
•The oesophagogastric (EG) mucosal junction.
•The diaphragmatic hiatus.
Indentations are caused by the aortic arch at 22 cm, the left main bronchus at 27 cm and the diaphragm at 38 cm. All distances vary according to the height of the individual. An enlarged left atrium may also indent the anterior aspect of the lower oesophagus.