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. Both types of lymph nodes are located within the trunk. Due to their location, abnormalities of the lymph nodes in the thorax 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. Computer tomography may be used to monitor any further changes once an abnormality is identified. For diagnostic purposes, lymph nodes of the thorax can be further divided into categories. The lung lymph nodes can be found along the bronchi. The paratracheal and tracheobronchial groups of lymph nodes accept drainage from the heart, lungs, bronchi, and thoracic trachea as well as other lymph nodes. The posterior mediastinal group of lymph nodes 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.