The Oesophagus
Definition
The first part of the alimentary tract
25 cm
Situation
Lies in the median plane in the thorax
In front of the vertebral column
Behind the trachea and the heart
Above it continues with the pharynx
Below it passes into the abdomen through an opening in the diaphragm called the oesophageal hiatus and joins the stomach
Important Parts
Upper end : cricoesophageal sphincter
Lower end : cardiac sphincter - physiological sphincter

Structure
Layers
Outer layer Adventitia - elastic fibrous tissue
Middle layer muscular coat
Inner layer of epithelium - upper third stratified squamous
epithelium, lower third columnar epithelium, middle third a mixture of the two
Blood Supply
Arterial supply : -
Oesophageal branches of the thoracic aorta
Abdominal part : inferior phrenic arteries, left gastric branch of the coeliac artery.
Venous drainage : -
Thoracic part drains into the azygos and hemiazygos veins
Abdominal part drains into the left gastric vein
A  venous plexus at the distal end connects the upward and downward venous drainage i.e. the general and portal circulation
Nerve supply
Sympathetic and parasympathetic nerves terminate in the myenteric and submucosal plexuses
Parasympathetic fibres from the vagus
Sympathetic fibres from thoracic sympathetic chain
Function
Propels the bolus down into the stomach
by peristaltic movements

Applied Anatomy
Cancer oesophagus    difficulty in swallowing
Achalasia Cardia      difficulty in swallowing - lower oesophageal sphinter relaxation impaired


   

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