Surgical Anatomy of Esophagus

Dr Pravin John and Dr John Thanakumar, Anurag Hospital, Coimbatore

1. Surgical anatomy of Esophagus Dr Pravin John Dr John Thanakumar , Trustee , IAGES ANURAG HOSPITAL COIMBATORE

2. Embryology

3. Although midline, Eso At neck - bulges to left In thorax midline At lower end curves across midline Abdominal - left Applied Anatomy Approach to Cervical - from Left Approach to Thoracic - from Right Chest Approach to Lower end- from left chest/abdominal Thoracic Esophagus is concave forwards

4. ANATOMY OF LOWER END - ESOPHAGUS 1.Supradiaphragmatic ( Ampullary) 2. Inferior oesophageal constriction 3.Vestibule(Intra abdominal) 4.Cardia APPLIED ANATOMY 1.Ampulla: Globular dilatation seen on barium - due to deep inspiration/Trendelenburg 2.Inferior Esophageal construction: at hiatal level, not synonymous with LES. High pressure zone extends to this 3.Vestibule : Inverted cone deviates to left to enter stomach at an angle from behind. Angle of His (1903)is the angle it makes with cardia. Angle is usually 70 - 110 degrees. Length is1.5 to 2 cm. Altered by gastric distension. 4.Cardia:

5. Cardia Imprecise to include lower end of Eso, CE Junction, & Upper stomach (Fabrius 1618). Cor is ‘heart’ Denotes CE junction with oblique fibres of stomach. Squamo columnar junction forms the distinct serrated Z line Z line at a variable distance from the cardia ( usually 1 cm proximal) Viewed from inside, it is a crescent, curving down and to the right It widens with age Angle of his (1903)is the angle it makes with cardia. Angle is usually 70 - 110 degrees.

6. ANATOMICAL RELATIONSHIPS CERVICAL SEGMENT: Anterior - Trachea with areolar tissue Posterior - Prevertebral layer of cervical fascia Lateral - Both recurrent laryngeal nerves (bet trachea and Eso) Carotid sheath ( vessels and vagi) Lobe of thyroid Inferior thyroid artery Lower neck: Eso deviates to left, closer to carotid sheath and thyroid lobe

7. THORACIC SEGMENT: in Superior mediastinum Anterior: Trachea till V thoracic vertebra Below this crossed by left bronchus Below this by pericardium and left atrium Posterior :Lies on pre vertebral fascia Vertebral column. From level of trachea bifurcation below, Azygos vein Thoracic Duct Right upper 5 IC arteries & Descending aorta

8. AZYGOS VEIN Originates in upper abdomen Enters chest via aortic opening Arches above root of Rt lung Enters IVC THORACIC DUCT Starts at Cisterna chill - L2 vert Enters chest via aortic opening Proceeds up to left Posterior to esophagus to Lie up on the left of esophagus

9. ABDOMINAL SEGMENT of Esophagus At hiatus,Eso passes anterior to aorta, a little to the left Covered by Gastrophrenic ligament, Lies behind the esophageal groove of left lobe of liver. Ant and Post Vagi in close apposition

10. ATTACHMENTS OF ESOPHAGUS Longitudinal muscles of Eso are inserted into cricoid cartilage. 3 attachments of Eso are: Accessory muscle bands Serosal reflections & Phreno esophageal membrane

11. STRUCTURE OF ESOPHAGUS 1.External fibrous layer 2.Muscular layer 3.Submucous Layer 4.Mucosal Layer

12. APPLIED ANATOMY 1.EXTERNAL FIBROUS LAYER

13. APPLIED ANATOMY 1.EXTERNAL FIBROUS LAYER

14. KILLIHAN’S DEHISCENCE & TYPE OF MUSCLES 2.MUSCLE LAYER Outer- thick longitudinal layer Inner- circular layer Killian's dehiscence is deficiency of longitudinal fibres at upper end Gives rise to Zenker’s diverticulum Circular fibres at lower end are thicker APPLIED ANATOMY

15. APPLIED ANATOMY 3. SUBMUCOUS LAYER Large vessels, moreso near cardia Site of collaterals in varies - portal hypertension 4.MUCOSAL LAYER Tough layer of stratified squamous epithelium with muscular mucosa Forms a rosette as longitudinal folds at lower end Squ-columnar junction is the dentate Z line with pale pink mucosa In GERD, junctional epithelium migrates upwards and replaces Squamous Epithelium. Called Barett’s oesophagus with high cancer risk.

16. ARTERIAL SUPPLY CERVICAL Inf thyroid artery Common carotid artery Superior thyroid artery Costo cervical trunk Vertebral artery THORACIC Bronchial arteries Direct from aorta ABDOMINAL Left gastric Left inferior phrenic

17. VENOUS DRAINAGE OF ESOPHAGUS As a plexus on the external surface of oesophagus NECK to inferior thyroid vein THORAX Azygos v Hemi Azygos v ABDOMINAL Left gastric (Coronary) vein APPLIED ANATOMY Varices in portal hypertension Zone 1 - Proximal stomach ( more veins in submucosa) Zone 2 - Distal esophagus ( more veins in lamina propria) Zone 3 - Proximal oesophagus ( more in submucosa)

18. LYMPHATIC DRAINAGE Networks between submucosa & mucosa LN are of 3 tiers. I tier - LN proximity to Eso Neck - Internal jugular Chest - Post tracheal, paratracheal Abdominal - Inf pulmonary, hiatal, cardiac II tier - LN in mediastinum at a distance III tier - Deep cervical Supraclavicular Tracheo bronchial Celiac LN

19. APPLIED ANATOMY In cancer mets Upper 2/3 to cervical Lower 1/3 to abdominal 3D LN-is cervico-thoraco-abdominal LN

20. NERVE SUPPLY OF ESOPHAGUS 1.Cranio sacral ( parasympthetics) 2.Thoraco lumbar ( sympathetic) 3.Intra mural plexus

21. ESOPHAGEAL HIATUS Enters via diaphragmatic hiatus Hiatus - anterior to aorta Slightly to left at X Thoracic vertebra 1.Rt crus splits into larger Rt and smaller left limbs 2.Rt crus splits equally into right and left sagittally 3.Scissor like attachments of Rt and Lt crus

22. MECHANISM OF CE JUNCTION COMPETENCE 1.Pinch cock of crural sling 2. Diaphragm 3.Oblique angle of entry of Eso 4.Cardiac angle (His) and incisuria 5.Oblique sling fibres of diaphragm 6.Mucosal rosette at CE junction 7.Phreno-esophageal membrane 8.Lungs 9.Lower esophageal sphincter 10.Liver tunnel

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