Anatomy of the oesophagus

anatomical description of the oesophagus for medical students and resident doctors

1. RELEVANT ANATOMY OF THE OESOPHAGUS BY DR GEORGE OWUSU

2. OUTLINE Introduction Embryology of the oesophagus Extent and parts of the oesophagus Relations of the oesophagus Blood supply and venous drainage Nerve supply of the oesophagus Lymph drainage of the oesophagus Structure of the oesophagus Clinical correlation Conclusion

3. INTRODUCTION The oesophagus is an important piece of the gastrointestinal tract and functions as a conduit for food and liquids that has been swallowed into the pharynx to reach the stomach. However, the smooth functionality of this organ may be impaired following certain diseased conditions resulting in poor muscular relaxation or increased intra-luminal pressure as may occur in Achalasia

4. EMBRYOLOGY OF THE OESOPHAGUS At the 4 th week, a respiratory diverticulum appears in the ventral wall of the foregut at the border with the pharynx. A tracheoesophageal septum forms, gradually separating the ventral respiratory diverticulum from the dorsal part of the fore gut hence, giving rise to a ventral Respiratory primodium and dorsally the Oesophagus. With the descent of the heart and oesophagus, the oesophagus which was initially short, lengthens rapidly.

5. EXTENT AND PARTS OF THE OESOPHAGUS The oesophagus is about 25cm long . E xtends from the lower border of the cricoid cartilage opposite the C6 vertebra to the cardiac orifice of the stomach. Its is divided into three parts Cervical part Thoracic part Abdominal part

6. RELATIONS OF THE OESOPHAGUS CERVICAL PART: Anterior relations: Trachea Thyroid gland Posterior relations: Lower cervical vertebrae Pre-vertebral fascia To the left: Left common carotid artery Left inferior thyroid artery Left subclavian artery Thoracic duct

7. RELATIONS OF THE OESOPHAGUS CERVICAL PART: To the right: Right common carotid artery Recurrent laryngeal nerves lie on either side in the groove between the oesophagus and trachea. THORACIC PART: Anterior relation: T rachea Left common carotid artery Left main bronchus Pericardium separating it from the left atrium

8. RELATIONS OF THE OESOPHAGUS THORACIC PART: Posterior relations: Thoracic vertebrae Thoracic duct Hemiazygous vein The descending aorta below To the left side: Left subclavian artery Aortic arch Left vagus nerve and its recurrent laryngeal branch Thoracic duct Left pleura To the right side: Right pleura Azygous vein

9. RELATIONS OF THE OESOPHAGUS Abdominal part : The right crus of the diaphragm as it passes through the diaphragm. Posterior surface of Left lobe of the liver Covered anteriorly and to the left with peritoneum.

10. BLOOD SUPPLY TO THE OESOPHAGUS: Cervical part: Inferior thyroid arteries Thoracic part: Bronchial arteries Esophageal branches from the aorta Abdominal part: Left gastric artery Inferior phrenic artery

11. VENOUS DRAINAGE OF THE OESOPHAGUS: CERVICAL PART: Inferior thyroid veins Thoracic part: Azygous veins Abdominal part: Azygous veins Left gastric veins

12. NERVE SUPPLY TO THE OESOPHAGUS UPPER THIRD: Parasympathetic supply from recurrent laryngeal nerve Sympathetic supply from middle cervical ganglion via the inferior thyroid artery Lower two-thirds: Parasympathetic supply by the vagi Sympathetic supply by the thoracic sympathetic chain.

13. LYMPHATIC DRAINAGE OF THE OESOPHAGUS Cervical part: Deep cervical nodes Thoracic part: Tracheobronchial nodes Posterior mediastinal nodes Abdominal part: Left gastric nodes Coeliac nodes

14. MICROSCOPIC STRUCTURE: The oesophagus from Lumina outward consist of the following layers: MUCOUS MEMBRANE: lined by non- keratinised stratified squamous epithelium. SUBMUCOSA: containing mucous glands MUSCULAR LAYER: consisting of an inner circular and outer longitudinal layer of muscles. (striated in upper one third and smooth in lower parts). SEROSA: outer layer of loose areolar tissue.

15. CLINICAL CORRELATIONS: OESOPHAGEAL CONSTRICTIONS: There are three narrow points in the oesophagus: Commencement of the oesophagus (17cm from upper incisors) Point crossed by the left main bronchus (28 cm from incisor) Diaphragmatic oesophageal opening (43cm from upper.

16. CONCLUSION The immense benefit of the proper functioning of the oesophagus cannot be overestimated in its effective role in natural human feeding. An adequate knowledge of the anatomy of the oesophagus is however key in tackling various diseases and conditions which may mar its adequate and proper function.

17. THANK YOU!!!!!!

18. REFERENCES Chummy sinnatamby. Lasts anatomy 12 th edition 2011. Frank Netter. Atlas of human anatomy 6 th edition 2014 Sadler T. W. et al. langmans medical embryology 9 th edition