**4. Connections that stabilize esophagus**

Fibrotic membrane that attaches esophagus to vertebral column is called "Bouteiller membrane." This membrane is tight over diaphragmatic hiatus and limits extreme movements of esophagus. However, under hiatus, membrane is loose and long. Phrenogastric ligament lies between diaphragm and cardia of stomach and both vagus nerves. Vagus nerves hang esophagus to thoracic cavity; thus, cutting vagus nerves elongates esophagus 4–5 cm [2].

#### **4.1. Arteries of esophagus**

Inferior thyroid artery provides primary arterial flow to the cervical esophagus, and subclavian artery, main carotid artery, vertebral arteries, ascendant pharyngeal artery, superficial cervical artery, and costocervical trunk are other arterial blood flow providers to cervical esophagus. Thoracic portion of esophagus takes blood flow from aorta, bronchial arteries, and right intercostal arteries. The abdominal esophagus is fed by left gastric artery, short gastric arteries, and descending branch of left phrenic artery. Inferior thyroid artery supplies arterial blood flow to cervical portion of esophagus (**Figure 6**). An excessively low resection of cervical esophagus causes devascularization to this area. In addition, aggressive resection and mobilization or laceration of bronchial artery, or cutting recurrent branches of left gastric artery and inferior phrenic artery causes devascularization at level of tracheal carina. Esophageal arterial blood flow is extremely rich and adequate for anastomosis, but a poor blood supply or careless or over aggressive dissection can cause anastomotic leakage in esophagus [14–16].

#### **4.2. Veins of esophagus**

Venous system of esophagus begins at submucosal plexus, which perforates muscular layer and empties into azygos system. Cervical portions of venous drainage empty into inferior thyroid veins. Thoracic portion's venous drainage empties into azygos vein, right brachiocephalic vein and, rarely, vertebral veins on right side, and hemiazygos vein, left brachiocephalic vein and, rarely, vertebral veins on left side. Venous drainage of abdominal portions empties primarily into left gastric veins. Other veins that drain esophageal venous plexus are short gastric veins, splenic vein, left gastroepiploic vein, and branches of an inferior phrenic vein. Lower esophageal veins connect to superior caval venous system by azygos and hemiazygos veins with multiple shunts, and other multiple shunts are located between inferior caval system and lower esophagus (**Figure 7**). Retrograde flow of esophageal venous system causes venous dilatation and varices, and these varices can cause fatal bleeding [2, 14, 17].

**Figure 6.** Relation among esophagus, diaphragm, and aorta (with permission from Turkish Surgery Association).

#### **4.3. Lymphatics of esophagus**

phrenoesophageal fascia, and transverse fascia of abdomen and peritoneum. Fibers of this ligament that reach upward are called "Juvara fibers"; downward fibers are called "Rouget fibers." Phrenoesophageal ligament resists vigorous abdominal pressure that pushes stomach to intrathoracic cavity, but it allows esophagus to move upward and downward while swallowing. This ligament makes gastroesophageal junction both flexible and tight [12, 13].

Fibrotic membrane that attaches esophagus to vertebral column is called "Bouteiller membrane." This membrane is tight over diaphragmatic hiatus and limits extreme movements of esophagus. However, under hiatus, membrane is loose and long. Phrenogastric ligament lies between diaphragm and cardia of stomach and both vagus nerves. Vagus nerves hang esophagus to thoracic cavity; thus, cutting vagus nerves elongates esophagus 4–5 cm [2].

Inferior thyroid artery provides primary arterial flow to the cervical esophagus, and subclavian artery, main carotid artery, vertebral arteries, ascendant pharyngeal artery, superficial cervical artery, and costocervical trunk are other arterial blood flow providers to cervical esophagus. Thoracic portion of esophagus takes blood flow from aorta, bronchial arteries, and right intercostal arteries. The abdominal esophagus is fed by left gastric artery, short gastric arteries, and descending branch of left phrenic artery. Inferior thyroid artery supplies arterial blood flow to cervical portion of esophagus (**Figure 6**). An excessively low resection of cervical esophagus causes devascularization to this area. In addition, aggressive resection and mobilization or laceration of bronchial artery, or cutting recurrent branches of left gastric artery and inferior phrenic artery causes devascularization at level of tracheal carina. Esophageal arterial blood flow is extremely rich and adequate for anastomosis, but a poor blood supply or careless or over aggressive dissection can cause anastomotic leakage in

Venous system of esophagus begins at submucosal plexus, which perforates muscular layer and empties into azygos system. Cervical portions of venous drainage empty into inferior thyroid veins. Thoracic portion's venous drainage empties into azygos vein, right brachiocephalic vein and, rarely, vertebral veins on right side, and hemiazygos vein, left brachiocephalic vein and, rarely, vertebral veins on left side. Venous drainage of abdominal portions empties primarily into left gastric veins. Other veins that drain esophageal venous plexus are short gastric veins, splenic vein, left gastroepiploic vein, and branches of an inferior phrenic vein. Lower esophageal veins connect to superior caval venous system by azygos and hemiazygos veins with multiple shunts, and other multiple shunts are located between inferior caval system and lower esophagus (**Figure 7**). Retrograde flow of esophageal venous system causes venous dilatation and varices, and these varices can cause fatal bleeding [2, 14, 17].

**4. Connections that stabilize esophagus**

**4.1. Arteries of esophagus**

12 Esophageal Abnormalities

esophagus [14–16].

**4.2. Veins of esophagus**

Lymphatics are located in every layer of esophagus, but primarily at lamina propria, forming a giant network system. Cervical lymphatics empty internal jugular lymph nodes and upper tracheal lymph nodes. An internal jugular lymphatic system that forms deeper cervical lymphatic system connects with lymphatic duct at right side and thoracic duct at left side.

Lymphatics of thoracic esophagus empty posterior parietal, diaphragmatic, tracheal, tracheobronchial, retrocardiac, and infracardiac lymph nodes.

**Figure 7.** Anti-reflux mechanism of esophagus.

Abdominal parts of lymphatic system empty left gastric, paracardiac lymph nodes, and all these nodes connect to coeliac lymph nodes. Coeliac lymph nodes empty cisterna chyli or thoracic duct.

Posterior parietal lymph nodes include posterior mediastinal and intercostal lymph nodes and connect with thoracic duct or right lymphatic duct. Only posterior part of diaphragmatic lymph nodes are connected to esophageal lymphatic system, and these lymph nodes empty to posterior parietal lymph nodes.

Tracheal or paratracheal lymph nodes are located on two sides of trachea, and tracheobronchial lymph nodes are located around bifurcation of trachea. Tuberculosis, which causes necrosis and fibrosis of tracheobronchial lymph nodes, forms traction diverticula of esophagus. These two lymphatic systems form a broch mediastinal lymphatic chain that empties to thoracic duct or right lymphatic duct (**Figure 8**) [18, 19].

#### **4.4. Innervation of esophagus:**

Parasympathetic and sympathetic nerves form esophageal innervation, carrying stimuli to esophageal muscles, glands, veins, and arteries.

#### *4.4.1. Parasymphatic innervation*

Parasympathatic fibers that innervate pharynx and upper part of esophagus come from ambiguous nuclei of brain. Esophageal innervation is primarily accomplished by vagus nerves, which end at dorsal vagal nuclei of brain. Cervical esophagus takes thin fibers from both recurrent laryngeal nerves. Both left and right recurrent laryngeal nerves arise from vagus nerves, but on left side, a recurrent laryngeal nerve is closer to aortic arch. On right side,

**Figure 8.** Lymphatics of esophagus.

Abdominal parts of lymphatic system empty left gastric, paracardiac lymph nodes, and all these nodes connect to coeliac lymph nodes. Coeliac lymph nodes empty cisterna chyli or thoracic duct. Posterior parietal lymph nodes include posterior mediastinal and intercostal lymph nodes and connect with thoracic duct or right lymphatic duct. Only posterior part of diaphragmatic lymph nodes are connected to esophageal lymphatic system, and these lymph nodes empty

Tracheal or paratracheal lymph nodes are located on two sides of trachea, and tracheobronchial lymph nodes are located around bifurcation of trachea. Tuberculosis, which causes necrosis and fibrosis of tracheobronchial lymph nodes, forms traction diverticula of esophagus. These two lymphatic systems form a broch mediastinal lymphatic chain that empties to

Parasympathetic and sympathetic nerves form esophageal innervation, carrying stimuli to

Parasympathatic fibers that innervate pharynx and upper part of esophagus come from ambiguous nuclei of brain. Esophageal innervation is primarily accomplished by vagus nerves, which end at dorsal vagal nuclei of brain. Cervical esophagus takes thin fibers from both recurrent laryngeal nerves. Both left and right recurrent laryngeal nerves arise from vagus nerves, but on left side, a recurrent laryngeal nerve is closer to aortic arch. On right side,

to posterior parietal lymph nodes.

**Figure 7.** Anti-reflux mechanism of esophagus.

14 Esophageal Abnormalities

**4.4. Innervation of esophagus:**

*4.4.1. Parasymphatic innervation*

thoracic duct or right lymphatic duct (**Figure 8**) [18, 19].

esophageal muscles, glands, veins, and arteries.

it is closer to subclavian artery. Finally, left and right recurrent laryngeal nerves run in sulcus between trachea and esophagus. The thoracic esophagus is primarily innervated by vagus nerves, but the upper part of thoracic esophagus takes some fibers from left recurrent laryngeal nerve. Vagus nerve fibers form two to four branches under tracheal bifurcation, and these nerve branches are located on anterior face of esophagus at level of posterior mediastinum. Near esophageal hiatus, these nerve branches unite and form two vagal trunks of esophagus. Variation of vagal trunks is important during vagotomy. A surgeon should be aware of these variations and be careful because more than one branch can be found in anterior or posterior vagal trunk or both.

#### *4.4.2. Sympathetic innervation*

The upper part of esophagus is innervated by pharyngeal plexus, which is fed by upper cervical ganglions, middle cervical ganglions, and sympathetic trunks of vertebral ganglions while running downward. Superior parts of the thoracic esophagus are innervated by stellate ganglion and subclavian ansa. Lower parts of thoracic esophagus are innervated by greater splanchnic nerves that end at coeliac plexus. Left greater splanchnic nerve and right inferior phrenic nerve innervate abdominal esophagus [20, 21].
