Thoracic plane

The thoracic plane is a plane used to divide the mediastinum into a superior mediastinum and inferior mediastinum.

This plane runs through the level of the sternal angle, (which is the joint between the manubrium and body of the sternum), between the intervertebral disc of T4 and T5.

The superior mediastinum extends superiorly above this plane, while the inferior mediastinum extends inferiorly. The inferior mediastinum is further divided into the posterior, middle and anterior compartments of the mediatinum.

Significant findings at the level of the thoracic plane:
1. The start (where the aortic arch comes out of the heart) and end of the arch of the aorta (where the arch of the aorta becomes the descending aorta)

2. The upper margin of the superior vena cava

3. The crossing of the thoracic duct

4. The bifurcation of the trachea

5. The bifurcation of the pulmonary trunk

6. The level of the Sternal Angle

7. The level of Rib 2 where it attaches to the sternum

8. The body of vertebrae T4