anatomy, physiology, and function of esophagus. oesophagus . structure of esophagus .

1. Anatomy and Physiology
of Oesophagus
Dr Himanshu Mishra
PG Resident
Department of ENT

2. APPLIED ANATOMY
• It is a fibro muscular tube, about 25 cm long in an
adult. It extends from the lower end of pharynx
(C6) to the cardiac end of stomach (T11)
• It shows three normal constrictions
1. At pharyngo-oesophageal junction (C6)—15 cm
from the upper incisors.
2. At crossing of arch of aorta and left main
bronchus (T4)—25 cm from upper incisors.
3. Where it pierces the diaphragm (T10)—40 cm
from upper incisors.

3. These areas are where most oesophageal
foreign bodies become entrapped.
• The most common site of
oesophageal impaction is at the
thoracic inlet
• About 70% of blunt foreign bodies
that lodge in the oesophagus do so
at this location
• Another 15% become lodged at the
mid oesophagus, in the region
where the aortic arch and carina
overlap the oesophagus on chest
radiograph.
• The remaining 15% become lodged
at the lower oesophageal sphincter
(LES) at the gastroesophageal
junction.

4. The wall of oesophagus consists of four layers.
(a) Mucosa, which is lined by stratified
squamous epithelium.
(b) Submucosa, which connects mucosa to
muscular layer.
(c) Muscular layer, which has inner circular and
outer longitudinal fibres.
(d) Fibrous layer, which forms loose covering of
oesophagus

5. NERVE SUPPLY
• Parasympathetic fibres come from vagus
nerves (X)
• sympathetic fibres from the sympathetic
trunk

6. LYMPHATIC DRAINAGE
• The cervical, thoracic and abdominal parts
drain respectively into deep cervical,
posterior mediastinal and gastric Nodes.

7. APPLIED PHYSIOLOGY
• Manometric studies have shown two high
pressure zones in oesophagus and they form the
physiological sphincters.
• The upper oesophageal sphincter starts at the
upper border of oesophagus and is about 3–5 cm
in length and functions during the act of
swallowing.
• The lower oesophageal sphincter is situated at
lower portion of oesophagus. It is also 3–5 cm in
length and functions to prevent oesophageal
reflux.

8. PHYSIOLOGY OF SWALLOWING
The act of swallowing is divided into three
phases:
• Oral or buccal phase. The food which is placed
in the mouth is chewed, lubricated with saliva,
converted into a bolus and then propelled into
the pharynx by elevation of the tongue against
the palate.

9. Pharyngeal phase. It is initiated when the bolus
of food comes into contact with pharyngeal
mucosa.
Oesophageal phase. After food enters the
oesophagus, the cricopharyngeal sphincter
closes and the peristaltic movements of
oesophagus take the bolus down the stomach.

10. Regurgitation of food back from stomach into
oesophagus is prevented by:
(i) tone of gastro-oesophageal sphincter,
(ii) negative intrathoracic pressure,
(iii) pinch-cock effect of diaphragm,
(iv) mucosal folds,
(v) oesophagogastric angle and
(vi) slightly positive intra-abdominal pressure.

11. THANK
YOU