Anatomy of the Mediastinum Quiz

The anterior mediastinum is a space in the chest located in front of the heart and within the mediastinum. It is bordered by the sternum anteriorly, the pericardium posteriorly, the diaphragm inferiorly, and the mediastinal pleura laterally.

The anterior mediastinum contains connective tissue, fat, remnants of the thymus gland, anterior mediastinal lymph nodes, the sterno-pericardial ligament, branches of the internal thoracic vessels, and the anterior border of the pleura and lung on the right side.

The middle mediastinum is a space in the chest that is bordered by the pericardium and contains the heart, great vessels, and some nerves.

Structures found within the middle mediastinum include the heart, the right and left phrenic nerves, the pericardiacophrenic vessels, the root of the great vessels (ascending aorta, SVC, pulmonary trunk, pulmonary veins), and the bifurcation of the trachea.

The posterior mediastinum is a space in the chest located behind the heart and within the mediastinum. It is bordered by the pericardium anteriorly, the vertebral column posteriorly, the mediastinal pleura laterally, and the diaphragm inferiorly.

The posterior mediastinum contains the descending thoracic aorta and its branches, the thoracic duct, posterior mediastinal lymph nodes (e.g., tracheobronchial nodes), the azygos and hemiazygos veins, the esophagus, the esophageal plexus, the thoracic sympathetic trunks, and the thoracic splanchnic nerves.

The right brachiocephalic vein is formed by the union of the right subclavian and right internal jugular veins, posterior to the sternoclavicular joint. It joins with the left brachiocephalic vein to form the superior vena cava.

The left brachiocephalic vein is formed by the union of the left subclavian and left internal jugular veins, posterior to the sternoclavicular joint. It crosses the midline posterior to the manubrium and joins with the right brachiocephalic vein to form the superior vena cava.

The major vein that carries deoxygenated blood from the head, neck, and upper limbs to the right atrium of the heart.

The point where the right and left brachiocephalic veins merge, marking the beginning of the superior vena cava.

A vein that collects blood from the back of the chest and abdomen, emptying into the superior vena cava.

The vein that carries blood from the left side of the chest and abdomen, connecting to the azygos vein.

The vein that carries blood from the upper left side of the chest and joins the azygos vein.

A procedure using large veins in the neck, shoulder, or chest to deliver fluids, medications, or blood.

Thin tubes inserted into veins to draw and return blood for patients with kidney failure.

The lower half of the superior vena cava, located within the protective sac around the heart.

A small branch of the brachiocephalic trunk that supplies blood to the thyroid gland. It is not always present.

The artery that carries blood to the left side of the head and neck. It arises from the aortic arch.

The artery that carries blood to the left upper limb. It arises from the aortic arch.

The part of the aorta that descends through the chest, supplying blood to the chest wall and internal organs.

Arteries that branch from the descending thoracic aorta and supply blood to the intercostal spaces, the spaces between the ribs.

Arteries that branch from the descending thoracic aorta and supply blood to the lower border of the 12th rib and the abdominal wall.

Large artery that carries deoxygenated blood from the right ventricle of the heart to the lungs. It later divides into right and left pulmonary arteries.

The part of the aorta that ascends from the heart and gives rise to the brachiocephalic trunk, left common carotid artery, and left subclavian artery.

A small, bilobed gland situated in the superior mediastinum behind the sternum.

The process of the thymus shrinking with age, starting after puberty.

The most anterior part of the superior mediastinum, directly behind the sternum.

The thymus receives blood supply from the inferior thyroid and internal thoracic arteries.

Lymphatic vessels that drain the thymus empty into the internal thoracic, tracheobronchial, and neck lymph nodes.

Parathyroid glands, which regulate calcium levels, can sometimes be found near or within the thymus.

The vagus nerve, a cranial nerve, travels through the mediastinum on its way to the abdomen.

The vagus nerve carries sensory information from the internal organs to the brain.

The right phrenic nerve descends along the right side of the pericardial sac, within the fibrous pericardium, anterior to the root of the right lung before exiting the thorax through the diaphragm alongside the inferior vena cava.

The left phrenic nerve enters the superior mediastinum, passing lateral to the left vagus nerve, before descending along the left side of the pericardial sac, within the fibrous pericardium, anterior to the root of the left lung. It then leaves the thorax by piercing the diaphragm near the apex of the heart.

Lymph vessels from the superficial skin of the anterior thoracic wall drain into the anterior axillary nodes.

Lymph vessels from the superficial skin of the posterior thoracic wall drain into the posterior axillary nodes.

Deep lymph vessels from anterior intercostal spaces drain forward to the internal thoracic nodes (parasternal nodes) along the internal thoracic vessels.

Deep lymph vessels from anterior intercostal spaces drain further to the thoracic duct on the left and the bronchomediastinal trunk on the right.

Deep lymph vessels from posterior intercostal spaces drain backward to the posterior intercostal nodes located near the heads of the ribs.

Deep lymph vessels from posterior intercostal spaces drain further to the thoracic duct.

The parasympathetic nervous system is part of the autonomic nervous system, responsible for "rest and digest" functions.

The connector cells of the parasympathetic system are located in the brain and the sacral segments of the spinal cord. In the brain, they are parts of the nuclei of cranial nerves III, VII, IX, and X. The sacral connector cells are found in the gray matter of the 2nd, 3rd, and 4th sacral segments of the spinal cord.

The sympathetic trunks are two ganglionated nerve trunks that extend the whole length of the vertebral column. They are made up of groups of nerve cells called ganglia.

Each sympathetic trunk has 3 ganglia in the neck, 11 or 12 ganglia in the thorax, 4 or 5 ganglia in the lumbar region, and 4 or 5 ganglia in the pelvis.

The thoracic part of the sympathetic trunk is continuous with the cervical and lumbar parts, and is located in the mediastinum running down the heads of the ribs.

The thoracic part of the sympathetic trunk has 12 (often 11) ganglia, each with white and gray rami communicans passing to the corresponding spinal nerve.

Gray rami communicantes carry postganglionic fibers from the sympathetic trunk to all the thoracic spinal nerves, while the first five ganglia give postganglionic fibers to the heart, aorta, lungs, and esophagus.

The lower eight thoracic ganglia primarily provide preganglionic fibers, which form the splanchnic nerves, supplying the abdominal organs.