Esophagus and Thoracic Duct Flashcards
Extent of the esophagus
Begins in the neck at the lower border of the cricoid cartilage, where it is continuous with the lower end of the pharynx
Descends in front of the vertebral column through the superior and posterior parts of the mediastinum
Pierces the diaphragm at the level of tenth thoracic vertebra
It ends by opening into the stomach at its cardiac end at the level of eleventh thoracic vertebra
Length of the esophagus
25 cm
Shape of the esophagus
The tube is flattened anteroposteriorly and the lumen is kept collapsed
When does the lumen of the esophagus dilate?
Passage of a food bolus
Where are the constrictions of the esophagus?
- Where the esophagus is crossed by cricopharyngeus muscle, 15 cm/6-inch from the incisor teeth
- Where it is crossed by the aortic arch, 22.5 cm/9-inch from the incisor teeth
- Where it is crossed by the left bronchus, 27.5 cm/11- inch from the incisor teeth
- Where it pierces the diaphragm 37.5 cm/15-inch from the incisor teeth
Distance from incisors is important for reference when passing endoscopes into the esophagus
What are the anterior relations of the thoracic part of the esophagus?
Trachea
Right pulmonary artery
Left bronchus
Pericardium with left atrium
The diaphragm
What are the posterior relations of the thoracic part of the esophagus?
Vertebral column
Right posterior intercostal arteries
Thoracic duct
Azygos vein with the terminal parts of the hemiazygos veins
Thoracic aorta
Right pleural recess
Diaphragm
What structures lie to the right of the thoracic part of the esophagus?
Right lung and pleura
Azygos vein
The right vagus
What structures lie to the left of the throracic part of the esophagus?
Aortic arch
Left subclavian artery
Thoracic duct
Left lung and pleura
Left recurrent laryngeal nerve, all in the superior mediastinum
What structures is the esophagus related to in the posterior mediastinum?
The descending thoracic aorta
The left lung and mediastinal pleura
Describe the arterial supply of the esophagus
Cervical part + segment up to the arch of aorta: Inferior thyroid arteries
Thoracic part: Esophageal branches of the aorta
Abdominal part: Esophageal branches of the left gastric artery
Describe the venous drainage of the esophagus
Upper part: Brachiocephalic veins
Middle part: Azygos veins
Lower end: Goes to the left gastric vein and vena azygos via hemiazygos vein
The low end of the esophagus is the site of the portosystemic anastomoses (anastomosis between portal and systemic venous systems)
Describe the lymphatic drainage of the esophagus
Cervical part: Deep cervical nodes
Thoracic part: Posterior mediastinal nodes
Abdominal part: Left gastric nodes
Nerve supply of the esophagus
Parasympathetic nerves:
Upper half: Recurrent Laryngeal Nerves
Lower half: Vagus
Sympathetic nerves:
Upper half: Middle Cervical Ganglion
Lower half: Upper four Thoracic Ganglia
Characteristics of the thoracic duct
Largest lymphatic vessel in the body
Extent of the thoracic duct
Upper part of the abdomen to the lower part of the neck
Length of the thoracic duct
45 cm
Reason for appearance of thoracic duct
Beaded appearance because of the presence of many valves in its lumen
Course of the thoracic duct
Begins as a continuation of the upper end of the cisterna chyli near the lower border of the T12 and enters the thorax through the aortic opening of the diaphragm
Ascends through the posterior mediastinum from level of T12 to T5, where it crosses from the right side to the left side
Passes through the superior mediastinum along the left edge of the esophagus and reaches the neck
In the neck, it arches laterally at the level of the transverse process of C7
Finally it descends in front of the first part of the left subclavian artery and ends by opening into the angle of junction between the left subclavian and left internal jugular veins
What are the tributaries of the thoracic duct?
The thoracic duct receives lymph from both halves of the body below the diaphragm and the left half above the diaphragm
Thorax: Lymph vessels from the posterior mediastinal nodes and from small intercostal nodes
Neck root: Efferent vessels of the nodes in the neck form the left jugular trunk, and those from nodes in the axilla form the left subclavian trunk. These trunks end in the thoracic duct.
Left bronchomediastinal trunk drains lymph from the left half of the thorax and ends in the thoracic duct
Right side: Right lymphatic duct into which the right bronchomediastinal, right jugular and right subclavian lymph trunks drain. The right lymphatic trunk ends in the right brachiocephalic vein at the junction of right subclavian and right internal jugular veins
