Oesophagus

What is the extent and course of oesophagus ?

Oesophagus is a muscular tube that conveys food from the pharynx to the stomach.

• Extent of oesophagus:
  • it  begins as continuation of pharynx in the neck at the lower border of the cricoid cartilage ( at the level of C6 vertebra) to the cardiac end of the stomach in the abdomen (opposite T11 vertebra)
  • Is 10 inches ( 25cm) long.
  • Is divided into three parts i.e. cervical, thoracic and abdominal.
• Course of oesophagus:
  • Cervical part (4cm):  descends behind the trachea and in front of the bodies of the  cervical vertebrae.
  • Thoracic part (20 cm): passes down through the superior and posterior mediastinum in from of thoracic vertebrae.  It lies behind the trachea in superior mediastinum and from the  bifurcation of trachea onwards, it passes behind the right  pulmonary artery. left principal bronchus and left atrium ( in the posterior mediastinum).
  •  Abdominal part (1-2cm): enters the abdomen by passing  through the opening in the diaphragm (at the level of T10 vertebral level. After a short course in the abdomen ( 2cm) opens in the cardiac end of stomach.

Enumerate the sites of constrictions of esophagus.

• Oesophagus has four constrictions:
  • 1^st constriction : at the beginning of oesophagus, at the level of C6 vertebra (15 cms/ 6 inches from incisor teeth ). This is the narrowest part of oesophagus. 
  • 2^nd constriction : where the arch of aorta crosses it, at the level of T3 vertebra ( 22.5 cms/9 inches from incisor teeth)
  • 3^rd constriction : where the left bronchus crosses it , at the level of T6 vertebra ( 27.5 cms/11 inches from incisor teeth )
  • 4^th constriction : where it passes through the diaphragm, at the level of T10 vertebra ( 40 cm/15 inches from incisor teeth)

Name the arteries that supply oesophagus.                                         

Arterial  that supply oesophagus are:

• Cervical part of oesophagus: oesophageal branches of  inferior thyroid artery.
• Thoracic part of oesophagus : oesophageal branches of descending thoracic aorta and bronchial arteries.
• Abdominal part of oesophagus : oesophageal branches of left gastric  and left inferior phrenic arteries.

Name the veins into which the oesophageal veins drain.

Venous drainage of oesophagus:

• Cervical part:  into inferior thyroid veins
• Thoracic part : into azygous and hemiazygous veins
• Abdominal part : into hemiazygous vein (tributary of inferior vena cava) & into left gastic vein ( tributary of portal vein)

 *Abdominal part of oesophagus is one of the sites portocaval anastomosis.

Enumerate the lymph nodes into which lymphatic drainage of oesophagus occurs.

Lymphatic drainage of oesophagus:

• Cervical part : into deep cervical nodes
• Thoracic part : into posterior mediastinal nodes draining into supraclavicular nodes
• Abdominal part : into left gastric nodes

*Hard fixed supraclavicular nodes may be palpated in patients with advanced oesophageal cancer.

Applied Aspects