QS Study

The oesophagus is a muscular, collapsible tube, about 10 inches long that joins the pharynx to the stomach. It is a part of the digestive system, which is sometimes called the gastrointestinal tract (GI tract). It is a long, muscular tube that connects your mouth to your stomach.

Length – 10 inch or 25 cm. Parts

Three parts –

(i) Cervical part.

(ii) Thoracic part.

(iii) Abdominal part.

Course

(a) It begins in the neck opposite the 6th cervical vertebra, where it is continuous with the pharynx.

(b) In the thorax, it passes downward and to the left through the superior and then the posterior mediastinum.

(c) It passes through the diaphragm at the level of T 10 vertebra and in the abdomen; it descends for about 0.5 inches (1.3 cm) and then enters the stomach.

Constrictions

(1) 1st – Where the pharynx joins the upper end, 15 cm from the upper incisor teeth.

(2) 2nd – Where the aortic arch and the left bronchus cross its anterior surface, 25 cm from the upper incisor teeth.

(3) 3rd – Where it is crossed by left bronchus, 27 cm from the upper incisor teeth.

(4) 4th – Where the oesophagus passes through the diaphragm into the stomach, 41 cm from the upper incisor teeth.

Fig: Oesophagus with sites of constrictions

Blood supply

Arterial supply

(1) Upper 1/3rd – by inferior thyroid artery.

(2) Middle 1/3rd – by branches from descending thoracic aorta.

(3) Lower 1/3rd – by branches from the left gastric artery.

Venous drainage

(1) Upper 1/3rd – Drain into inferior thyroid veins.

(2) Middle 1/3rd – Drain into azygos vein.

(3) Lower 1/3rd – Drain into a left gastric vein.

Lymphatic drainage

Lymph vessels from the:

i) Upper third – drain into deep cervical nodes.

ii) Middle third – drain into superior and posterior mediastinal nodes.

iii) Lower third – drain into nodes along the left gastric blood vessels and the coeliac nodes.

Nerves supply

i) Parasympathetic: Vagus nerve.

ii) Sympathetic: Sympathetic trunks.

iii) Oesophageal nerve plexus.

Histological structure

(1) Mucosa – lined by non-keratinized stratified squamous epithelium.

(2) Submucosa – Contain glands.

(3) Muscular layer.

(4) Adventitial layer.