anterior mediastinum (anatomy)
Last reviewed 01/2018
The anterior mediastinum is the region bounded by:
- anteriorly: the sternum
- posteriorly: the anterior border of the fibrous pericardium
- superiorly: an arbitrary plane passing horizontally and posteriorly from the manubriosternal joint to the inferior border of the T4 vertebra
- inferiorly: diaphragm
- laterally: anterior mediastinal pleura overlying the lungs
The anterior mediastinum is the smallest of all the compartments within the mediastinum. In the adult, it is only a potential space that contains the thymus remnants. It is relatively much bigger in infants in whom the thymus is at its most extensive.