Dr Craig Hacking and Dr Jeremy Jones et al.

The mediastinum is a space in the thorax that contains a group of non-delineated organs and their surrounding connective tissue. It lies in the midline of the chest between the pleura of each lung and extends from the sternum to the vertebral column

Gross anatomy

The mediastinum contains all the thoracic viscera except the lungs: heart and great vesselsoesophagustracheaphrenic nervecardiac nervethoracic ductthymus, and mediastinal lymph nodes.

Anatomical division

The mediastinum can be divided into parts based on their relationship to the fibrous pericardium:

An alternative ITMIG classification has been proposed based on cross-sectional imaging 2

  • superiorly: continuous with the loose connective tissue of the neck
  • anteriorly: chest wall
  • laterally: lungs and pleura
  • posteriorly: thoracic spine
  • inferiorly: diaphragm

Related pathology 

Broadly, pathology that affects the mediastinum can be divided into those that result in a focal mass, or those that result in diffuse disease involving the mediastinum. Additionally, air may track into the mediastinum in pneumomediastinum.

The differential diagnosis of a focal mediastinal mass is highly dependant on its location within the mediastinum, resulting in specific differential lists for:

Diffuse mediastinal disease can be separated into groups depending on whether the mediastinal disease is smooth or lobulated:

Thoracic anatomy
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Article information

rID: 14548
System: Chest
Section: Anatomy
Synonyms or Alternate Spellings:

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Cases and figures

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    Figure 1: Mediastinum (Gray's illustration)
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    Figure 2
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    Normal mediastina...
    Case 1: normal paediatric mediastinal anatomy (CT)
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