Anatomy

The oesophagus is a tubular structure, approximately 25 cm long, extending from the laryngeal part of the pharynx at the level of the 6th cervical vertebra, passing through the diaphragm at the level of the 10th thoracic vertebra to join the stomach at the oesophagogastric (OG) junction (Figure 1.1). For purposes of practicality during endoscopic procedures, the site of a lesion in the oesophagus is given as the distance from the upper incisor teeth. As it is approximately 16 cm from the upper incisor teeth to the proximal oesophageal limit, the OG junction is at approximately 40-41 cm. The oesophagus traverses the neck, thorax and enters the abdominal cavity and so can be anatomically divided into three sub-sites:

1. Cervical oesophagus: 2-3 cm long and extends from the proximal oesophageal limit (C6) to the thoracic inlet, which is marked by the surface landmark of the suprasternal notch of the sternum (breast bone).

2. Intrathoracic oesophagus: approximately 21 cm long and extends from the thoracic inlet to the oesophageal hiatus in the diaphragm. At 25 cm from the upper incisor teeth the oesophagus is constricted by the aortic arch and the left main bronchus crossing its anterior surface.

3. Abdominal oesophagus: 1-1.5 cm long and extends from the oesophageal hiatus in the diaphragm to the right side of the stomach. It is covered anterolaterally by peritoneum and comes into close relationship with the left lobe of liver.

An internal landmark of relevance to determining the site of origin of an oesophagogastric tumour is the OG junction where the pale oesophageal squamous mucosa meets the glandular mucosa of the gastric cardia. The OG junction can be somewhat irregular in outline (the Z line) and does not necessarily correspond to the lower physiological valve or sphincter. External landmarks are distal oesophagus orientated to adventitial fat while the junctional area and proximal stomach relate to a covering of serosa or peritoneum. Thus, a tumour of the distal oesophagus or OG junction can spread through the wall either to adventitial fat of the mediastinum or the abdominal peritoneum. Adventitial fat is disposed laterally, but absent anteriorly and posteriorly where the oesophagus is adjacent to the heart and vertebral column respectively. Note that the adventitia of the mid-oesophagus may also relate to a serosal surface - that of resected mediastinal pleura.

As well as determining the position of the lesion within the oesophagus by its anatomical site, it can also be defined by its relative position in the upper, middle or lower third of the oesophagus. This is of relevance clinically as the lymphovascular drainage is considered in these terms and is therefore important in cancer surgery.

Upper Middle Lower Third Anatomy
Figure 1.1. Oesophagus. Reproduced with permission from Hermanek P, Hutter RVP, Sobin LH, Wagner G, Wittekind Ch (eds.). TNM Atlas: illustrated guide to the TNM/pTNM classification of malignant tumours, 4th edition. Springer-Verlag: Berlin and Heidelberg, 1997.

The regional lymph nodes are, for the cervical oesophagus, the cervical nodes including supraclavicular nodes and, for the intrathoracic oesophagus, the perioesophageal, subcarinal, mediastinal and perigastric nodes, excluding those at the origin of the coeliac artery

The regional lymph nodes are, for the cervical oesophagus, the cervical nodes including supraclavicular nodes and, for the intrathoracic oesophagus, the perioesophageal, subcarinal, mediastinal and perigastric nodes, excluding those at the origin of the coeliac artery

Anatomy Perigastric Nodes
Figure 1.2. Oesophagus: regional lymph nodes. Reproduced with permission from Hermanek P, Hutter RVP, Sobin LH, Wagner G, Wittekind Ch (eds.). TNM Atlas: illustrated guide to the TNM/pTNM classification of malignant tumours, 4th edition. SpringerVerlag: Berlin and Heidelberg, 1997.
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Responses

  • sanna
    What is a 1.5 cm odemetous lesion at the og junction in the body?
    4 years ago

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