 Okay, good afternoon everybody. I'll be presenting today a topic of Ace of Vegas. I'll be discussing a few things about Ace of Vegas today. That will include embryology, histology and anatomy and some physiology of the Ace of Vegas. Starting from this diagram which shows early digestive system and blood supply to an embryo, if you see at the middle, you'll see that this is the primordial gut with the blood supply in the back and the dorsal surface. And there is a small bud here which I'll be referring to very soon. So embryology of the Ace of Vegas during the fourth week of the foregut development, a small diverticulum appears in the ventral surface adjacent to the pharyngeal gut. That is the small diverticulum I showed in the previous slide. This is the tracheobronchial diverticulum. Subsequently, it elongates and separates, gradually separate from the dorsal foregut by an esophageal tracheal septum. And that separates the Ace of Vegas from the tracheal. The remaining part of the foregut rapidly elongates in the craniocautal growth of the embryonic body, forming the digestive system. That's the Ace of Vegas. So if you see in this diagram, this is the foregut. And it's getting separated from the respiratory tract by tracheal esophageal septum. Okay, starting from this, this is from the front. And this is the respiratory tract forming the trachea and the bilateral bronchi. And this is the pharynx and this is the Ace of Vegas. Okay, why did I mention that? Because any abnormality can lead to some congenital problem. This includes esophageal atresia. Esophageal atresia leads to polyhydraminous because the embryo cannot swallow that amniotic fluid. And we have the tracheal esophageal fistula, esophageal stenosis, and congenital high telhernia. Congenital high telhernia can happen in two different types. If the Ace of Vegas is too short, the whole stomach and the junction between the Ace of Vegas and the stomach will be pulled up or it can be just sliding that the cardiac side, cardiac junction only will be pulled up. I didn't mention, get the pictures of that because this presentation is about the Ace of Vegas. Okay, these are some type of congenital tracheal esophageal fistula. If you see here, it's completely, the fistula with the upper part and the lower part is completely blunt. Coming down here, you see two types, two fistulas are there between the upper and the lower part. And here they have one single fistula and there is a continuation of the full Ace of Vegas. And in this one, there is atresia of the upper part and the lower part is completely separated without fistula. And this one is a place of the trachea and this is very little condition where there is no respiratory tract. Okay, histology of the Ace of Vegas. The Ace of Vegas also has four layers as any other GI tract, but it differs in the sense that it doesn't have cirrhosa. So it has the fibrosis. If we see the Ace of Vegas from outside inward, we find that fibrosis cord, muscular cord, then submucosa and mucosa. The muscular cord has two different type of muscles that's external longitudinal muscle and inner circular muscles. And the submucosa, it contains a lot of allure tissue and fatty tissue, which provides mobility to the Ace of Vegas. Then it also contains blood vessels, nerve, lymphatics, and mucous glands. The mucosa is folded into folds in longitudinal folds, which makes it easy for the food to pass through and when it expands. Okay, so, and it consists of different type of three layers, which is muscularis mucosa, connected tissue, and then you have the epithelium, which is stratified squamous epithelium and becomes junction columnar epithelium at the lower one to two centimeter just near the car decorefus of the stomach. Now coming to the gross anatomy of the Ace of Vegas. Starting, what is Ace of Vegas? It is a flattened muscular tube around 18 to 26 centimeter from the upper sphincter to the lower sphincter. It connects the pharynx to the stomach. It commences at the lower border of the carcuit cartilage at level of C6. It descends in front of the spine through a posterior mediastinum, passes through the diaphragm and entering the abdomen. It terminates at the car decorefus of the stomach, opposite to 11 thoracic vertebra. Okay, the direction of the Ace of Vegas. During the descendant of the Ace of Vegas, it turns to the left twice. That's at the root of the neck, starting from here. At the root of the neck, it turns to left once. Then it goes back to the midline again. Sorry, from here to here, it's the root of the neck. Then it goes back to midline again. Then again, once it disperses the diaphragm, it turns to left again. So it has two lateral curves, both going to left twice. Coming to sphincters of Ace of Vegas. It has two sphincters, that's upper sphincter and lower sphincter. The upper sphincter is at level of C6, formed by the inferior pharyngeal constrictor, merged with the caricopharyngeus muscle. That is the upper sphincter. Then the lower sphincter is only the circular muscles at level of T6, which has a high term. Okay, coming to constrictions of the Ace of Vegas, which are important for while doing the endoscopies. In Ace of Vegas, you have around three constructions. The first constriction is at 15 centimeter, then second is 25 centimeter, and the third one is at 40 centimeter. The first constrictor is the same like the upper Ace of Vegas sphincter. Then the second one is formed when the aortic arch passes in front of the Ace of Vegas and the main left bronchus. And the last one is when the Ace of Vegas disperses the diaphragm. Seeing that the same thing from the side, this picture shows the constrictor from the side. If you see at this side where the Ace of Vegas starts, this is the upper sphincter, and this is the outer part that passes in front of the Ace of Vegas, and this is the main left stem of the bronchus. This is the second sphincter, and this is here the third sphincter when the Ace of Vegas passes into the abdomen. Okay, how Ace of Vegas is divided? It's divided into three parts. One is cervical part, one is thoracic part, and the last one is abdominal part. So I'll discuss all the parts separately. I'll just give brief things about each part. So starting with the cervical Ace of Vegas, it extends from the pharyngeal Ace of Vegas junction at the lower border of the first thoracic vertebra, and it's around five to six centimeter. At this level, the Ace of Vegas, this is the relation with what I'm going to mention. It's bordered anteriorly by the trachea and recurrent laryngeal nerves, and posteriorly by vertebral column, pre-vertebral muscle, and pre-vertebral layer of deep cervical fascia. And the lateral is the common carotid arteries and the posterior portion of the thyroid gland. Then coming to thoracic Ace of Vegas, it extends from the lower border of first thoracic vertebra to the diaphragmatic hiatus. It passes posterior to the trachea, the tracheal bifurcation, and the main left stem bronchus. And it lies posterior and to the right of the aortic artery at the level of T4. And from level of T8, until the diaphragmatic hiatus, the Ace of Vegas lies anteriorly to the order. I'll come to some diagram very soon. Then abdominal Ace of Vegas, it's the shortest part, which is extend from the diaphragmatic hiatus to the cardiac orifice of the stomach. It is cone-shaped, about one centimeter long. The base of the Ace of Vegas transitions smoothly into the cardiac orifice. The abdominal Ace of Vegas lies on the posterior surface of the left lobe of the liver. That's known as the esophageal groove, which is directly related to crust of the diaphragm and left inferior phrenic artery. Okay, the relation of the vagus nerve to the abdominal Ace of Vegas is like as follow. Left vagus nerve lies in the anterior wall of the Ace of Vegas, while the right lies posterior to the Ace of Vegas. That's due to embryonic rotation of the stomach. Okay, this picture shows that this is from front and this is from the back. This is the Ace of Vegas, and it's crossed by the aorta at this level. And this is the trachea and the left main bronchus. And if you see the same thing from the back, you see how the aorta crosses. It's starting from here, crosses the Ace of Vegas, and cause this is the first second constrictor I talked about. Then it passes backward, downward, going to posterior surface of the Ace of Vegas. So from the level of T8 downward, the aorta lies posterior to the Ace of Vegas. Okay, and if you see here, you have the right and left crura diaphragm, where both of them, they form the orifice of the Ace of Vegas orifice while entering the abdomen. So coming to blood supply, the blood supply of Ace of Vegas is very copious blood supply. So it is segmented blood supply. It's supplied by inferior thyroid artery which supplies the upper Ace of Vegas sphincter and cervical Ace of Vegas. Then you have the esophageal arteries and the branches of bronchial arteries supplies the thoracic esophagus and left gastric artery and branches of left phrenic or splenic artery supply the lower esophageal sphincter. And this is the segment of Ace of Vegas. And due to this copious blood supply, it's very rare to have esophageal infarction or leak while doing anestomosis in the Ace of Vegas. So this diagram shows that blood supply of Ace of Vegas. You have the carotids and the inferior thyroid artery from this side. And if you see these black lines at the bronchial, tracheopronchial arteries and esophageal arteries, and from this side, this is what you call it, celiac trunk giving splenic artery and left gastric artery. Just to remember, you can remember the other way. You have the cervical thoracic and abdominal esophagus. Each part of the Ace of Vegas shares two organs, it's blood supply. Like the cervical esophagus shares the thyroid gland and the trachea. And thoracic esophagus shares the trachea and bronchi. And abdominal esophagus shares the stomach and spleen. Okay, venous drainage. It's again segmental. It formed dense submucosal plexus of the venous blood drains into the superior venaquiva. The veins of the proximal and distal esophagus drain into the azagus system. Collateral of the left gastric vein, branch of portal vein, receives venous drain from the mid-esophagus. The submucosal connection between the portal and systemic venous system in the distal esophagus form the esophageal varicis, which can be a cause of bleeding, GI bleed. So this diagram shows that venous drainage of the esophagus will show the superior venaquiva and azagus system. This is the hemis azagus vein and this is the portal system with the gastric veins. Nerve supply, it has a parasympathetic and sympathetic nerve supply. The parasympathetic nerve supply is from the vagus nerve and provide motor innervation of the esophagus and secretive motor innervation to the gland. So the motor and secretive motor are from the vagus. The systemic blood supply, you can remember that the sympathetic, sorry, the sympathetic blood supply is all going to the smooth muscles. So it's from T1 to T10, it regulates blood vessels, constructions, esophagus sphincter contraction and relaxation and muscular wall and increases glandular and peristaltic activity. So if you see, all of them are related to smooth muscle like blood vessels, esophagus constructor and the muscles of the esophagus. I don't know how clear it is, but this is the lymphatic drainage of the esophagus. So we have three parts. Can you see it or it's quite, it looks good. Oh, pretty well. Okay. Okay, I can divide into upper third, middle third and lower third of the esophagus. The upper third go to supraclavicular lymph node and middle third goes to superior medialisthenic nodes and posterior medialisthenic nodes and the lower third goes to the celiac nodes. So all the parts together goes at the end to thoracic lymphatic duct. Okay, and drain into lymphatic, sorry, right lymphatic duct. Okay, going to short physiology of esophagus. Obviously everybody knows that esophagus transmits the foods from the mouth to and pharynx into the stomach. So it's primary conduct food from pharynx to the stomach and it movements organically specifically in this of this function. Normally it has two type of peristalsis that's primary peristalsis and secondary peristalsis. The primary peristalsis constitute a peristaltic wave that begins at the pharynx and spread into the esophagus during pharyngeal stage of swelling. It passes all the way from the pharynx into the stomach. It is around eight to 10 seconds. So you remember that the swelling has three phases which is oral phase, pharyngeal phase, sorry, esophageal, oral phase, pharyngeal phase and esophageal phase. So that started the pharyngeal stage. Then secondary peristalsis results from the extension of the esophagus by retained food and it continues until the food has emptied into the stomach. Okay, the upper esophageal sphincter which I mentioned previously is normally closed with excessive tone and does not allow any entry of air into the esophagus during inspiration. The mean resting pressure of the upper sphincter is around 14 millimeter mercury. During swelling, it relaxes for seconds and allowed food to descend down. Then the tone increased up to 100 millimeter mercury which pushes the bolus of the food downward into the esophagus. And the primary peristalsis start that time. Okay, what happens after that? The food will descend down. Within the thorax, interaluminal pressure is minus five to five, minus five during inspiration and five during expiration. When the bolus passes down, the pressure reaches around 25 millimeter mercury with the peristalsis wave. What happens at the lower sphincter? Normally remains tonically constructed with pressure of around 30 millimeter mercury and contrast to the mid portion of the esophagus which is usually relaxed. When the peristaltic wave passes downward, there is a receptive relaxation of lower esophageal sphincter ahead of the peristaltic wave which allow easy propulsion of the food into the stomach. Lower pressure can cause acid reflex disease. I'm sorry. I just listed out some very common disorders of esophagus but I'm not going to talk about them. I'm sure you will be having some idea about them. Maybe zincers diverticulum is worth mentioning which is there is a part of the pharyngeal, it's pharyngeal diverticulum at the upper part of the esophagus. It's not supported by muscle posteriorly. So it's a false diverticulum where the mucus of the pharynx just goes from the diverticulum and just behind the esophagus. Okay. I'm so confused. Okay.