Anatomy of the Oesophagus PDF

# Vv. pulmonales - Vv. pulmonales follow the arteries and bronchi and are located in the mediastinum medium. - The pulmonary arteries and veins are located exclusively in the mediastinum medium. - The same applies to the thoracic part of the inferior vena cava. - The superior vena cava is located i...

# Vv. pulmonales - Vv. pulmonales follow the arteries and bronchi and are located in the mediastinum medium. - The pulmonary arteries and veins are located exclusively in the mediastinum medium. - The same applies to the thoracic part of the inferior vena cava. - The superior vena cava is located in the mediastinum superior and medium. - The aorta is located in the mediastinum medium, superior and posterior. # Ductus thoracicus - Ductus thoracicus originates from the abdominal cavity. - It runs through the diaphragm and continues along the spine, first through the posterior mediastinum and then through the superior mediastinum. - Ductus thoracicus leaves the thoracic cavity through the superior thoracic aperture. - Three major nerves originate from the neck and run through the mediastinum from top to bottom. These nerves are: - n. vagus - truncus sympaticus - n. phrenicus - Each nerve runs through the superior thoracic aperture and the superior mediastinum, but then they separate. - The n. vagus and the truncus sympaticus, the two major visceral nerves, run through the posterior mediastinum. - The n. phrenicus, the diaphragm’s motor nerve, continues through the mediastinum medium. - All three nerves run through the diaphragm into the abdominal cavity. # The oesophagus in the neck - In the neck, the oesophagus is located behind the trachea and the thyroid gland. - It runs in front of the vertebral column and between the right and left lateropharyngeal spaces containing the major neck vessels and nerves. - The trachea’s lumen is open, while the oesophagus is collapsed. - The thyroid gland is located anterior to the trachea and consequently also anterior to the oesophagus. - It extends to the sides of both tubes. - An enlarged thyroid gland can compress the oesophagus causing dysphagia (difficulty swallowing). # The oesophagus in the thorax - In the superior mediastinum, the oesophagus is located behind the trachea, in front of the vertebral column and between the right and left lung and pleura. - In the posterior mediastinum, the oesophagus runs with the thoracic aorta. - Together, they are located behind the heart and pericardium, in front of the vertebral column and between the right and left lung and pleura. - The oesophagus is located in a groove on the liver in the abdominal cavity. ## Structure of the oesophagus - The oesophagus is lined by a mucous membrane, the tunica mucosa. - It is pale and generally loosely bound. - The tunica mucosa forms longitudinal folds, so that the lumen appears star-shaped when viewed in cross-section. - When food passes through the oesophagus, the folds disappear. - The lining epithelium of the mucous membrane is stratified squamous epithelium, non-keratinized. - This is because the oesophagus functions as a food conduit. - The deepest layer of the mucous membrane is the lamina muscularis mucosae. - It clearly separates the tunica mucosa from the submucosa. # Tunica mucosa of the oesophagus - The tunica mucosa of the oesophagus consists of three layers: - lamina epithelialis - lamina propria - lamina muscularis mucosae - Mucous membranes of the oral cavity and pharynx consist only of epithelium and connective tissue. - The third layer, the lamina muscularis mucosae, starts in the upper end of the oesophagus and continues directly through the stomach and the entire intestinal tract to the anus. # Tela submucosa of the oesophagus - The submucosa, also called the tela submucosa, binds the mucous membrane very loosely and contains only a few glands in humans. - There are only a few glands needed in the oesophagus because food is chewed and mixed with large amounts of saliva in the mouth. - In dogs, who swallow food whole, there are many glands in the oesophagus since they need to produce mucus to lubricate the wall. # The oesophagus - The oesophagus is a 25cm long tube. - It conveys food from the pharynx to the stomach. - The oesophagus follows the anterior surface of the vertebral column from the caudal part of the cervical region to the caudal part of the thoracic region. - In the neck, the oesophagus is located in the visceral space. - In the thoracic cavity, the oesophagus is located first in the superior mediastinum and then in the posterior mediastinum. - The oesophagus perforates the diaphragm and then has a very short course in the abdominal cavity.