Final answer:
The anterior mediastinum contains lymph nodes, the thymus gland (in children), connective tissue, and internal thoracic vessels. It lies within the thoracic cavity, anterior to the pericardial cavity and posterior to the sternum.
Step-by-step explanation:
The anterior mediastinum is a region in the thoracic cavity, specifically a part of the ventral cavity in the human body. It is situated in front of the pericardial cavity and behind the sternum. The anterior mediastinum contains a few structures, which may vary slightly among individuals, but generally it includes lymph nodes, the thymus gland in children (which can atrophy in adults), fat, and connective tissue. This area is also associated with the internal thoracic vessels and the sternopericardial ligaments. The mediastinum itself also encompasses other important anatomical structures besides the anterior mediastinum, such as the heart, which is enclosed by the pericardial cavity, and the trachea, esophagus, and major blood vessels.