Anatomy of esophagus

ANATOMY OF ESOPHAGUS

Dr. Chinamilli JaahnaviPostgraduate MS (Gen. surgery)

EMBRYOLOGY

o Development begins in week 3 of gestation

o Derived from the endoderm lined yolk sac cavity- primitive gut

o A ventral diverticulum develops during week 3- tracheobronchial tree

o Mucosa completely differentiated by week 12

o Muscular layer develops from the mesoderm beginning in week 6 and

completely formed by week 12

o First functional swallow is seen at about week 14 and well established

by 4months gestation

GROSS ANATOMY

25 cm long muscular tube From lower border of

cricoid to stomach C6 to T11 2 curves in coronal plane 3 constrictions

PARTS

ESOPHAGUS is mainly studied in 3 parts:

CERVICAL

THORACIC

ABDOMINAL

All anatomical features, pathologies, surgical approach

and management options are specific to each of these

parts.

RELATIONS- CERVICAL PART

Anteriorly- trachea

Posteriorly- prevertebral muscles an fascia

covering 6th to 8th cervical vertibrae

Laterally- carotid sheath, lower poles of the

thyroid gland

The thoracic duct is found on left side at C6 level

RELATIONS- THORACIC PART

RELATIONS- ABDOMINAL PART

Very short segment of variable length

o Anteriorly- esophageal groove on

posterior surface of the liver

o Related to greater sac anteriorly

and on the left.

o Lesser sac peritoneum found on the

right side

o Closely related to the vagus nerves

GASTRO ESOPHAGEAL JUNCTION

Externally- Collar of Helvetius, Gastroesophageal fat pad

Endoscopically- Z line, Transition from smooth

lining in esophagus to rugal folds in the stomach.

.

BLOOD SUPPLY

CERVICAL PART-

Inferior thyroid artery

THORACIC PART-

Bronchial and esophageal

branches of the descending

aorta ABDOMINAL PART-

Ascending branches of the left

phrenic and left gastric arteries.

VENOUS DRAINAGE

Submucosal plexus

Periesophageal venous plexus

Esophageal veins

• CERVICAL- Inferior thyroid vein• THORACIC- Azygos vein,

Hemiazygos veins, Intercostal veins, Bronchial veins

• ABDOMINAL- Left gastric vein

Porto systemic anastomosis

NERVE SUPPLY

o ENTERIC NERVOUS SYSTEM- Auerbach’s plexus in the

intermuscular plane

Meissner’s plexus in the submucosal

plane

o EXTRINSIC NERVOUS SYSTEM- Parasympathetic supply from the

vagus via recurrent laryngeal nerves

Sympathetic supply from thoracic

spinal cord segments

LYMPHATIC DRAINAGEo Lymphatic plexuses in submucosa and

muscularis regional lymph nodes

o Cervical esophagus- Paratracheal, Deep cervical, Internal jugular nodes

o Thoracic part- Mediastinal nodes, Paratracheal, Subcarinal, Retro cardiac Infracardiac lymph nodes Thoracic duct.

HISTOLOGY

4 LAYERS Mucosa- stratified squamous

epithelium Submucosa- containing

brenners glands Muscularis propria- inner

circular and outer longitudinal

muscle fibres Adventitial layer

THERE IS NO SEROSAL LAYER ON ESOPHAGUS

Schematic Representation