Neha Patil (Editor)

Mediastinum

Updated on
Edit
Like
Comment
Share on FacebookTweet on TwitterShare on LinkedInShare on Reddit
Latin
  
mediastinus

TA
  
A07.1.02.101

Dorlands /Elsevier
  
m_06/12518945

FMA
  
9826

Mediastinum

The mediastinum (from Medieval Latin mediastinus, "midway") is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, trachea, phrenic and cardiac nerves, the thoracic duct, thymus and lymph nodes of the central chest.

Contents

Structure

The mediastinum lies within the thorax and 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 behind, and contains all the organs of the thorax except the lungs. It is continuous with the loose connective tissue of the neck.

The mediastinum can be divided into an upper (or superior) and lower (or inferior) part:

  • The superior mediastinum starts at the superior thoracic aperture and ends at the thoracic plane.
  • The thoracic plane separates the superior and inferior mediastinum. It is a plane at the level of the sternal angle , and the intervertebral disc of T4–T5.
  • The inferior mediastinum from this level to the diaphragm. This lower part is subdivided into three regions, all relative to the pericardium - the anterior mediastinum being in front of the pericardium, the middle mediastinum contains the pericardium and its contents, and the posterior mediastinum being behind the pericardium.

    • Anatomists, surgeons, and clinical radiologists compartmentalize the mediastinum differently. For instance, in the radiological scheme of Felson, there are only three compartments (anterior, middle, and posterior), and the heart is part of the anterior mediastinum.

    Superior mediastinum

    The 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.

    • Thoracic plane

  • The thoracic plane separates the superior and inferior mediastinum. It is a plane at the level of the sternal angle, and the intervertebral disc of T4–T5.

    • A number of structures occur at the level of the thoracic plane, which divides the superior and inferior mediastinum:

    compiled by

    Inferior mediastinum

    Anterior mediastinum

    Is bounded:

  • laterally by the pleurae;
  • posteriorly by the pericardium;
  • anteriorly by the sternum, the left transversus thoracis and the fifth, sixth, and seventh left costal cartilages.

    • References

    Mediastinum Wikipedia
    (Text) CC BY-SA