Human Anatomy Vol 1

THORAX

nerves, and the lower half by the oesophageal plexus

formed mainly by the two vagi. Parasympathetic

nerves are sensory, motor and secretomotor to the

oesophagus.

2 Sympa.thetic neroes: For upper half of oesophagus,

the fibres come from middle cervical ganglion and

run with inferior thyroid arteries. For lower half,

the fibres come directly from upper four thoracic

ganglia, to form oesophageal plexus before

supplying the oesophagus. Sympathetic nerves are

vasomotor.

The oesophageal plexus is formed mainly by the

parasympathetic through vagi but sympathetic fibres

are also present. Towards the lower end of the

oesophagus; the vagal fibres form the anterior and

posterior gastric nerves which enter the abdomen

through the oesophageal opening of the diaphragm.

In portal hypertension, the communications

between the portal and systemic veins draining

the lower end of the oesophagus dilate. These

dilatations are called oesophageal aarices. Rupture

of these varices can cause serious haematemesis

or vomiting of blood. The oesophageal varices can

be visualised radiographically by barium swallow;

they produce worm-like shadows (Fig.20.6).

Left atrial enlargement as in mitral stenosis can

also be visualised by barium swallow. The

enlarged atrium causes a shallow depression on

the front of the oesophagus. Barium swallow also

helps in the diagnosis of oesophageal strictures,

carcinoma and achalasia cardia.

The normal indentations on the oesophagus

should be kept in mind during oesophagoscopy

(Fig.20.7).

The lower end of the oesophagus is normally kept

closed. It is opened by the stimulus of a food bolus.

In case of neuromuscular incoordination, the

lower end of the oesophagus fails to dilate with

the arrival of food which, therefore, accumulates

in the oesophagus. This condition of neuro-

muscular incoordination characterised by inability

of the oesophagus to dilate is known as 'achalasia

cardia' (Fig.20.8). It may be due to congenital

absence of nerve cells in wall of oesophagus.

Improper separation of the trachea from the

oesophagus during development gives rise to

tracheo-oesophageal fistula (Fig. 20.9).

Compression of the oesophagus in cases of

mediastinal syndrome causes dysphagia or

difficulty in swallowing.

rnl'.,
l'

Fig. 20.6: Oesophageal varices

lndentation caused by aortic arch

lndentation caused by left bronchus

Shallow indentation caused by left atrium

Diaphragm

Fig.20.7: Normal indentations of oesophagus

No peristalsis

Oesophageal

dilation due to

back-up of food

Lower oesophageal

sphincter fails to

relax

Fig. 20.8: Achalasia cardia

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