Oesophagus

At a glance

English

Oesophagus

Latin (TA2)

Oesophagus

System

Digestive

Region

Thorax

Side

Single, on the midline

About the oesophagus

The oesophagus, or gullet, is about 25 cm long in an adult. It begins in the neck at the lower border of the cricoid cartilage, level with the sixth cervical vertebra, as the continuation of the laryngopharynx. It then runs down through the superior and posterior mediastinum, passes through the diaphragm at about the tenth thoracic vertebra; a short way below, opposite the eleventh, it joins the stomach at the cardia. At rest it is flattened from front to back; it opens only as a bolus passes.

Along the way it keeps close company with other organs, and these leave their marks. In the neck it lies behind the trachea, with the recurrent laryngeal nerves in the grooves between them. In the chest it is crossed on its left by the arch of the aorta and then by the left main bronchus, and lower down it lies behind the left atrium of the heart. It is narrowed at its start, where the aortic arch and left bronchus cross it, and where it passes the diaphragm. The vagus nerves spread over it as the oesophageal plexus and gather again into front and back trunks that pass through the diaphragm with it.

Its wall has the four layers typical of the gut: a lining of non-keratinised stratified squamous epithelium, a submucosa with mucous glands, a muscular coat of inner circular and outer longitudinal fibres, and an outer adventitia rather than a serosa above the diaphragm. The muscle is skeletal in the upper third, mixed in the middle and smooth in the lower third. An upper sphincter, formed mainly by cricopharyngeus, and a functional lower sphincter at the junction with the stomach stay closed between swallows. Swallowing triggers a wave of peristalsis that pushes the bolus down in a few seconds.

If the lower sphincter is weak, stomach acid washes back and causes heartburn (reflux disease); long-standing reflux can change the lining at the lower end into a columnar type, called Barrett's oesophagus, which carries a risk of cancer. In liver disease with raised portal pressure, the veins at the lower end, where portal and systemic veins meet, can swell into varices that may bleed heavily. Failure of the lower sphincter to relax, achalasia, makes swallowing difficult.

Function and supply

Begins at

Continues from the laryngopharynx at the lower border of the cricoid cartilage, level with the sixth cervical vertebra.

Ends at

Ends just below the diaphragm at the cardiac orifice of the stomach, roughly opposite vertebra T11.

Function

Moves swallowed food and fluid to the stomach by peristalsis, while its sphincters stop air entering from above and stomach contents rising from below.

Nerve supply

Vagus nerves through the oesophageal plexus (recurrent laryngeal nerves for the upper part) with sympathetic fibres from the cervical and thoracic sympathetic trunks.

Blood supply

Inferior thyroid arteries in the neck, oesophageal branches of the thoracic aorta and bronchial arteries in the chest, and the left gastric and left inferior phrenic arteries for the abdominal part.