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/Abdominal oesophagus and stomach/ABDOMINAL OESOPHAGUS

CHAPTER 65 – Abdominal oesophagus and stomach

ABDOMINAL OESOPHAGUS

The abdominal oesophagus is 1–2.5 cm in length, and is slightly broader at the cardiac orifice than the diaphragmatic aperture. It lies to the left of the midline and enters the abdomen through the oesophageal aperture (formed by the two diaphragmatic crura) opposite the level of the tenth thoracic vertebra. It runs obliquely to the left and slightly posteriorly, and ends at the gastro-oesophageal junction/cardiac orifice of the stomach. The abdominal oesophagus lies posterior to the left lobe of the liver, which it grooves slightly, anterior to the left crus, the left inferior phrenic vessels and the left greater splanchnic nerve; its surface is covered in a thin layer of connective tissue and visceral peritoneum which contains the anterior and posterior vagi as well as the oesophageal branches of the left gastric vessels. The anterior vagus may be single or composed of multiple trunks, and is closely related to the outer fibres of the longitudinal muscle coat of the oesophagus. The posterior vagus is usually a single trunk and is less closely applied to the oesophageal muscle within the loose connective tissue, which makes its identification during surgery somewhat easier.

The abdominal oesophagus is effectively tethered to the diaphragm by connective tissue (Fig. 65.1); the phreno-oesophageal ligament. This is formed of two thickened bands of elastin-rich connective tissue; the inferior phreno-oesophageal ligament is effectively an extension of the transversalis fascia extending beneath the parietal peritoneum as it is reflected from the diaphragm onto the abdominal oesophagus. The fibres are only loosely attached to the adventitial tissues and a variable amount of fat often lies beneath it, between the oesophageal wall and the crural sling. This oesophageal fat pad tends to act to tether the oesophagus to the fibres of the crura but tends to regress with age. On the thoracic side of the diaphragm the superior phreno-oesophgeal ligament is similarly formed from an extension of the subpleural endothoracic fascia. It is denser than its inferior counterpart with more elastin present and is tethered much more firmly through the muscle fibres of the oesophageal wall into the submucosal tissues. It may well act to restore lower oesophageal position after the movement engendered by the peristalsis of swallowing (Kwok et al 1999). Anteriorly, the subperitoneal connective tissue is particularly dense and blends with both the outer layer of the oesophageal wall and the apex of the crural fibres of the diaphragm. On the posterior aspect the peritoneal reflection is extremely short since the crura lie steeply angled, and the posterior oesophageal wall has a much shorter ‘effective length’ than the anterior. This short reflection of peritoneum is sometimes referred to as the gastrophrenic ligament and, via the peritoneum over the oesophagus continues directly onto the posterior surface of the stomach. It covers the oesophageal branches of the left gastric vessels and the coeliac branches of the posterior vagus and can thus be said to form an extremely short, wide mesentery to the abdominal oesophagus. In all but the thinnest individuals a pad of adipose tissue is found beneath the peritoneum covering the anterior surface of the lower abdominal oesophagus and the adjacent gastric wall. It is a useful surgical marker for the external location of the gastro-oesophageal junction.

  

Fig. 65.1  The anatomical structures around the abdominal oesophagus.
(Reprinted from Netter Anatomy Illustration Collection, © Elsevier Inc. All Rights Reserved.)

VASCULAR SUPPLY AND LYMPHATIC DRAINAGE

Arteries

The abdominal oesophagus is supplied by oesophageal branches of the left gastric artery. These ascend as an anterior and posterior branch beneath the visceral peritoneum to supply perforating branches to the intramural and submucosal plexuses. The posterior surface usually receives an additional supply via branches of the upper short gastric arteries, the terminal branches of the oesophageal branches of the thoracic aorta and occasionally an ascending branch of the posterior gastric artery.

Veins

Veins drain via plexuses to the left gastric and upper short gastric veins (see Stomach veins below).

Lymphatic drainage

Lymphatic drainage occurs to the left gastric and left and right paracardial nodes and from the posterior surface directly to the uppermost para-aortic nodes (see Fig. 65.13).

  

Fig. 65.13  Main lymph node stations of the stomach and upper abdominal viscera. The sagittal relationships of the node groups around the neck of the pancreas are shown bottom right. The para-aortic nodes are among the highest nodes for these viscera but have been removed for clarity (see Ch. 66).

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