Thoracic lymph nodes are separated into two types: parietal lymph nodes located in the thoracic wall, and visceral lymph nodes, which are associated with the internal organs. Due to their location, abnormalities of the lymph nodes in the thorax, or chest, are not easily detected. However, any changes in the size or amount of these lymph nodes could be indicative of several types of extrapulmonary or pulmonary diseases. For diagnostic purposes, lymph nodes of the thorax can be further divided into sub-categories. The lung lymph nodes can be found along the bronchi. The paratracheal and tracheobronchial groups of lymph nodes are located in the neck and also in the junction where the trachea meets the bronchi, respectively. These accept drainage from the heart, lungs, bronchi, and thoracic trachea as well as other lymph nodes. The posterior mediastinal group of lymph nodes, located near the thoracic aorta, is closely linked to the tracheobronchial group and primarily drains into the thoracic duct. The chest wall thoracic lymph nodes receive drainage from the breasts, arms, pectoral muscles, and other muscles and skin located in the upper section of the chest.