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sqadia.com is a solution for medical students where they can get high quality medical video lectures along with PowerPoint presentations by numerous medical specialists. The lecture posterior thorax aims to elaborate the vertebral origin of thoracic duct, the azygos system of veins, and also information about mediastinum is given alongside Warda Naz highlights the medical importance of superior and inferior mediastinum.
Esophagus, Trachea and Aorta
At sqadia.com, anatomy demonstrator Warda Naz delivers detailed medical lecture of anatomy course on the topic of posterior thorax. This section of the anatomy lecture is based on esophagus, trachea and aorta. Esophagus is a muscular tube connecting pharynx with stomach. Just before entering stomach, it passes through diaphragm. Trachea is a cartilaginous tube, connecting pharynx and larynx to lungs. The aorta is the largest artery which begins at top of left ventricle. The anterior relations of the thoracic part of the esophagus from superior to inferior are the trachea, right and left bronchi, pericardium. The esophageal impressions indicate where swallowed foreign bodies are most likely to lodge. The continuous anastomotic chain of arteries on the esophagus is formed by branches of the right and left inferior thyroid and right supreme intercostal arteries, the unpaired median aortic branches, branches of the left gastric and left inferior phrenic arteries inferiorly.
The lecture posterior thorax made by following the medical book ¨Grant's Atlas of Anatomy¨ for MBBS students also focuses on the medical aspects of thoracic duct. The thoracic duct originates from the cisterna chyli at the T12 vertebral level and ascends on the vertebral column between the azygos vein and the descending aorta passes to the left at the junction of the posterior and superior mediastina. The termination of the thoracic duct typically receives the left jugular, subclavian, and broncho-mediastinal trunks. Because the thoracic duct is thin-walled and may be colourless, it may not be easily identified. Consequently, it is vulnerable to in- advertent injury during investigative and/or surgical procedures in the posterior mediastinum. The lymph vessels of the skin of the anterior thoracic wall drain to the anterior axillary nodes. The lymph vessels of the skin of posterior thoracis wall drain to the posterior axillary nodes.
Azygos System of Veins
Azygos system of veins is discussed comprehensively in the medical video lecture at the platform of sqadia.com for medical and MBBS students. The ascending lumbar veins connect the common iliac veins to the lumbar vein. Then join the subcostal veins to become the lateral roots of the azygos and hemi-azygos veins. The medial roots of the azygos and hemi- azygos veins are usually from the inferior vena cava and left renal vein. The hemi-azygos vein crosses the vertebral column at approximately T9. The accessory hemi-azygos vein crosses at T8, to enter the azygos vein. The azygos vein arches superior to the root of the right lung at T4 to drain into the superior vena cava. When obstruction of the SVC occurs superior to the entrance of the azygos vein, blood can drain inferiorly into the veins of the abdominal wall and return to the right atrium through the IVC and azygos system of veins.
At sqadia.com, according to the medical syllabus of anatomy course, mediastinum is also discussed under the chapter of posterior thorax. The mediastinum is the central compartment of the thoracic cavity surrounded by loose connective tissue. It contains a group of structures within the thorax. The contents of mediastinum are the heart and its vessels, the esophagus, trachea, phrenic, cardiac nerves. Anatomically, mediastinum lies within the thorax. It is enclosed on the right and left by pleurae. It is surrounded by the chest wall in front, the lungs to the sides and the spine at the back. It extends from the sternum in front to the vertebral column. Parts of mediastinum are superior mediastinum and inferior mediastinum.
Superior and Inferior Mediastinum
Warda Naz also elaborates superior and inferior mediastinum comprehensively for the ease of medical students. Superior mediastinum is bounded superiorly by the thoracic inlet, the upper opening of the thorax, inferiorly by the transverse thoracic plane, laterally by the pleurae, anteriorly by the manubrium of the sternum, posteriorly by the first four thoracic vertebral bodies. Anterior mediastinum is bounded laterally by the pleurae, posteriorly by pericardium, anteriorly by the sternum. Contents of anterior mediastinum are some lymphatic vessels which ascend from the convex surface of the liver, two or three anterior mediastinal lymph nodes, the small mediastinal branches of the internal thoracic artery, and thymus. Middle mediastinum is bounded by pericardial sac. Posterior mediastinum is bounded anteriorly by bifurcation of trachea, inferiorly by thoracic surface of diaphragm.