Areas - Middle Mediastinum

Question 1

Borders?

Answer 1

Anterior - anterior margin of the pericardium.

Posterior - posterior border of the pericardium.

Laterally - mediastinal pleura of the lungs.

Superiorly - imaginary line extending between the sternal angle (the angle formed by the junction of the sternal body and manubrium) and the T4 vertebrae.

Inferiorly - superior surface of the diaphragm.

Question 2

Contents?

Answer 2

Organs

1) heart
2) pericardium
3) tracheal bifurcation

Vessels

1) ascending aorta - gives rise to the coronary arteries.
2) pulmonary trunk - gives rise to the right and left pulmonary arteries.
3) SVC - formed by the right and left brachiocephalic veins.

Nerves

1) cardiac plexus - derived from T1-T4 segments of the spinal cord. Parasympathetic supply is derived from the vagus nerve. The plexus can be divided into the superficial and deep components.
2) phrenic nerves (left and right) - mixed nerves the provides motor innervation to the diaphragm. They arise in the neck, and descend through the middle mediastinum to reach the diaphragm.

Lymphatics

The tracheobronchial lymph nodes are located within the middle mediastinum. They are a group of nodes associated with the trachea and bronchi of the respiratory tract - and are characteristically enlarged in certain lung pathologies. They form from the gathering of bronchial nodes within the hila of the lungs. Individual groups of nodes are connected via fine lymphatic channels.