Post on 22-Mar-2017
transcript
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