Esophagus Flashcards
The esophagus is a narrow muscular tube extending from
Pharynx to Stomach
The anatomy of
esophagus is clinically important because of its involvement in various diseases such as
Esophagitis, esophageal varices
and cancer.
Dimensions
Length: 25 cm (10 inches).
Width: 2 cm
The lumen of esophagus is
Closed (collapsed) and opens (dilates) only during the
passage of the food.
The course of esophagus:
It starts at lower border of Cricoid Cartilage @ C6 Level and then decends downwards in front of vertebral column passing thru’ superior and posterior mediastina and the pierces the diaphragm at T10 level and ends at Cardiac orifice at T11 Level
The CURVATURES of Esophagus :
- Two side-to-side curvatures, both towards the left.
(a) First at the root of the neck, before entering the thoracic inlet.
(b) Second at the level of T7 vertebra, before passing in front of the descending thoracic aorta. - Two anteroposterior curvatures.
(a) First corresponding to the curvature of cervical
spine.
(b) Second corresponding to the curvature of thoracic
spine.
How many constrictions are there in esophagus and the distance to each one is measured from?
There are four sites of anatomical constrictions/
narrowings in the esophagus. The distance of each constriction is measured from the upper incisor teeth.
The First Constriction :
The pharyngo-esophageal junction,
9 cm (6 inches) from the incisor teeth.
It is due to Upper Esophageal Sphincter : Cricopharyngeus
The Second Constriction :
Here it is crossed by the arch of
aorta, 22.5 cm (9 inches) from the incisor teeth
The Third Constriction :
Here it is crossed by the left principal bronchus, 27.5 cm (11 inches) from the incisor teeth.
The Forth Constriction :
Here it pierces the diaphragm, 40 cm (15 inches) from the incisor teeth.
The esophagus is divided into
3 Parts
- Cervical part (4 cm in length).
- Thoracic part (20 cm in length).
- Abdominal part (1–2 cm in length).
The cervical part extends from
The lower border of cricoid
cartilage to the superior border of manubrium sterni
The Thoracic Part Extends From
Superior border of manubrium sterni to the esophageal opening in the diaphragm
The Abdominal Part Extends From
Esophageal opening in the diaphragm to the cardiac end of the stomach.
RELATIONS OF THORACIC PART OF THE ESOPHAGUS 1. Anterior
- Trachea.
- Arch of aorta.
- Right pulmonary artery.
- Left principal bronchus.
- Left atrium enclosed in the pericardium.
- Diaphragm.
RELATIONS OF THORACIC PART OF THE ESOPHAGUS 2. Posterior
- Vertebral column.
- Right posterior intercostal arteries.
- Thoracic duct.
- Azygos vein.
- Hemiazygos veins (terminal parts).
- Descending thoracic aorta.
RELATIONS OF THORACIC PART OF THE ESOPHAGUS 3. Right
- Right lung and pleura.
- Azygos vein.
- Right vagus nerve.
RELATIONS OF THORACIC PART OF THE ESOPHAGUS 4. Left
- Arch of aorta.
- Left subclavian artery.
- Thoracic duct.
- Left lung and pleura.
- Left recurrent laryngeal nerve.
- Descending thoracic aorta.
RELATIONS OF ABDOMINAL PART OF THE ESOPHAGUS
Anterior: 1. Posterior surface of the left lobe of the liver. 2. Left gastric nerve. Posterior: 1. Left crus of diaphragm. 2. Right gastric nerve.
Blood Supply to the esophagus
Cervical part : Inferior Thyroid Arteries
Thoracic part : Esophageal Branches of
(a) descending thoracic aorta, and
(b) bronchial arteries.
Abdominal part : Esophageal Branches of
(a) left gastric artery, and
(b) left inferior phrenic artery.
VENOUS DRAINAGE of Esophagus
Cervical part is drained by inferior thyroid veins.
Thoracic part is drained by azygos and hemiazygos veins.
Abdominal part is drained by two venous channels, viz.
(a) hemiazygos vein, a tributary of inferior vena cava, and
(b) left gastric vein, a tributary of portal vein.
LYMPHATIC DRAINAGE of Esophagus
Cervical Part : Deep cervical
Thoracic Part : Posterior mediastinal lymph nodes.
Abdominal Part : Left gastric lymph nodes.
Nerve Supply
The parasympathetic fibres are derived from recurrent
laryngeal nerves and esophageal plexuses formed by vagus
nerves. They provide sensory, motor, and secretomotor
supply to the esophagus.
The sympathetic fibres are derived from T5–T9 spinal
segments are sensory and vasomotor.
