Mediastinum

Mediastinum

1. Inferior Mediastinum

   • Anterior
     • Borders
       • Anterior- sternum and transversus thoracic muscles
       • posterior- pericardium
     • Contents: fat, connective tissue, sternopericardial ligamen, and thymus in children
   • Middle
     • Borders
       • anterior and posterior- borders of pericardium
       • lateral- mediastinal surface of lungs
       • inferior- superior diaphragm
     • contents: heart, root of great vessels, and trachea bifurcation
   • Posterior
     • Borders
       • Anterior- pericardium
       • Posterior- T5-T12 vertebrae
       • Lateral- mediastinal surface of lungs
     • Contents: Descending/thoracic aorta, azygos vein, hemiazygos vein, accessory hemiazygos vein, thoracic duct, esophagus, sympathetic trunk, vagus nerve and trunk

2. Superior Mediastinum

   • Borders: 1st rib to Sternal angle of Louis (T4)
   • Planes
     • Glandular
       • Thymus gland
         • Most anterior
     • Venous
       • Right and Left Brachiocephalic Veins
         • Including Right and Left Internal Jugular veins and subclavian veins
       • Superior Vena Cava
         • Brachiocephalic veins drain into superior vena cava
       • Arch of Azygos vein
         • Stems off the posterior side of superior vena cava
     • Arterial- nervous
       • Aortic arch
         • Brachiocephalic trunk, left common carotid artery, and left subclavian artery
       • Left and Right Vagus nerves
       • Left and right Phrenic nerves
     • Visceral
       • Trachea
       • Esophagus
       • Left Recurrent Laryngeal Nerve
       • Thoracic Duct
     • Lymphatic
       • Most posterior