Human Anatomy: Mediastinum and Pericardium

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Questions and Answers

What is the location of the oblique sinus in relation to the heart?

Post surface of the left atrium (correct)

Front surface of the heart

Superior surface of the aorta

Left ventricle

Which artery supplies the fibrous pericardium?

Pericardiacophrenic artery (correct)

Brachiocephalic artery

Pulmonary artery

Coronary artery

Which structure is located behind the oblique sinus?

Esophagus (correct)

Pulmonary trunk

Aorta

Left atrium

What type of nerve supplies the fibrous pericardium and parietal layer of the serous pericardium?

Phrenic nerve Signup and view all the answers

Which statement is true regarding the transverse sinus of the serous pericardium?

It lies between the reflection around the aorta and pulmonary trunk. Signup and view all the answers

Which structure is found in the middle mediastinum?

Heart Signup and view all the answers

What structures bound the superior mediastinum anteriorly?

Manubrium sterni Signup and view all the answers

Which of the following is NOT a part of the inferior mediastinum?

Superior mediastinum Signup and view all the answers

Which nerves are present in the superior mediastinum?

Vagus and phrenic Signup and view all the answers

What structure is located posteriorly in the superior mediastinum?

Upper 4 thoracic vertebrae Signup and view all the answers

Which part of the mediastinum contains the pulmonary trunk?

Middle mediastinum Signup and view all the answers

The anterior mediastinum is bounded by which of the following?

Body of sternum Signup and view all the answers

What is a key structure located within the superior mediastinum?

Left recurrent laryngeal nerve Signup and view all the answers

What is the main function of the pericardium?

To restrict excessive movements of the heart Signup and view all the answers

Which structure is NOT found in the posterior mediastinum?

Pulmonary trunk Signup and view all the answers

What type of fluid is found in the pericardial cavity?

Serous fluid Signup and view all the answers

What is located posterior to the body of the sternum?

Fibrous pericardium Signup and view all the answers

Which nerve is NOT part of the contents of the posterior mediastinum?

Left common carotid nerve Signup and view all the answers

Which of these vessels does the fibrous pericardium fuse with?

Inferior vena cava Signup and view all the answers

Where does the serous pericardium reflect to?

To cover the heart Signup and view all the answers

Which structure is NOT part of the boundaries of the posterior mediastinum?

Inferior vena cava Signup and view all the answers

Study Notes

Mediastinum

Located between the lungs, mediastinum is part of the thoracic cavity.
Divided into superior and inferior sections at the T4 vertebra (angle of Louis).
Inferior mediastinum further divided into anterior, middle (contains heart and great vessels), and posterior areas adjacent to T5–T12 vertebrae.
Boundaries include:
- Superior: Thoracic inlet and root of neck
- Inferior: Diaphragm
- Anterior: Sternum
- Posterior: 12 thoracic vertebrae

Superior Mediastinum

Boundaries:
- Above: Thoracic inlet
- Below: Line through sternal angle and T4-T5 intervertebral disc
- Anterior: Manubrium sterni
- Posterior: Upper four thoracic vertebrae
Contains sternohyoid and sternothyroid muscles, remnant of thymus gland, aortic arch, and major arteries (e.g., brachiocephalic, left common carotid, left subclavian arteries).
Includes several nerves (right/left vagus, right/left phrenic, left recurrent laryngeal), cardiac branches of autonomic nerves, trachea, esophagus, thoracic duct, and groups of lymph nodes.

Anterior Mediastinum

Boundaries:
- Front: Body of sternum
- Behind: Pericardium
Contains superior and inferior sternopericardial ligaments, thymus gland, and a few lymph nodes.

Middle Mediastinum

Contains pericardium and multiple important structures:
- Within pericardium: heart, ascending aorta, pulmonary trunk, parts of superior and inferior vena cava, pulmonary veins.
- Outside pericardium: trachea bifurcation, principal bronchi, pulmonary arteries, and phrenic nerves.

Posterior Mediastinum

Boundaries:
- Front: Pericardium and diaphragm
- Behind: 5th to 12th thoracic vertebrae
Contains descending thoracic aorta, azygos vein, hemiazygos veins, esophagus, vagus nerves, splanchnic nerves, sympathetic trunks, thoracic duct, and lymph nodes.

Pericardium

A fibroserous sac enclosing the heart and great vessel roots, located in the middle mediastinum behind the sternum and 2nd to 6th costal cartilages.
Functions to restrict excessive heart movement and provide lubrication for contractions.

Types of Pericardium

Fibrous Pericardium:
- Strong fibrous layer attached to the diaphragm and fuses with great vessels (ascending aorta, pulmonary trunk, vena cavae).
Serous Pericardium:
- Composed of parietal and visceral layers; the former lines the fibrous pericardium, while the latter closely adheres to the heart (epicardium).
Pericardial Cavity:
- The space between parietal and visceral layers containing pericardial fluid, which serves as a lubricant.

Pericardial Sinuses

Oblique Sinus: Located on the posterior surface of the heart, bordered by large veins and the entrance bounded by IVC and pulmonary veins.
Transverse Sinus: Short passage between reflections around the aorta/pulmonary trunk and large veins, positioned anterior to the ascending aorta.

Arterial Supply of Pericardium

Fibrous and parietal layers are supplied by pericardiacophrenic artery, branches from descending aorta, and musculophrenic artery.
Visceral layer is supplied by coronary arteries.

Nerve Supply of Pericardium

Fibrous and parietal layers: Sensory fibers from the phrenic nerve and sympathetic fibers.
Visceral layer: Innervated by autonomic nervous system via cardiac plexuses.

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Description

Explore the intricate anatomy of the mediastinum and pericardium in this quiz. Learn about the divisions of the thoracic cavity and the vital structures contained within. Perfect for students of human anatomy seeking to deepen their understanding of this essential area.