Superior mediastinum

The superior mediastinum is that portion of the interpleural space which lies between the manubrium sterni in front, and the upper thoracic vertebrae behind.

Boundaries
It is bounded:
 * below by a slightly oblique plane passing backward from the junction of the manubrium and body of the sternum to the lower part of the body of the fourth thoracic vertebra (see also thoracic plane)
 * laterally by the pleurae

Contents

 * muscles
 * origins of the Sternohyoidei and Sternothyreoidei
 * lower ends of the Longi colli
 * arteries
 * aortic arch
 * brachiocephalic artery
 * thoracic portions of the left common carotid and the left subclavian
 * veins
 * innominate veins and
 * upper half of the superior vena cava
 * left highest intercostal vein
 * nerves
 * vagus nerve
 * cardiac nerve
 * superficial and deep cardiac plexuses
 * phrenic nerve
 * left recurrent nerve
 * trachea
 * esophagus
 * thoracic duct
 * remains of the thymus
 * some lymph glands
 * anterior longitudinal ligament