Lymphatic System

The lymphatic system of the lung includes intrapulmonary lymph nodes (N-1) and mediastinal lymph nodes (N-2). The intrapulmonary nodes are within the visceral pleural envelope. These are shown in Figure 11.6. The mediastinal lymph nodes are also shown in Figure 11.6. They can be classified numerically to include node stations 1, 2, 3, 4, 5, 6, 7, 8 and 9. It should be noted that level 10 nodes may be considered either intrapulmonary or mediastinal, depending on the level that they are sampled at. They are more likely to be intrapulmonary on the left side because the left mainstem bronchus is longer than that on the right.

With regard to the N-2 nodes, these are mediastinal nodes and can be also classified into the following four categories:

1) Paratracheal nodes: These include nodes around the level of the trachea and include level 1, 2 and 3 nodes.

2) Tracheobronchial nodes include node stations 4, 10 and 7. The level 7 node is an important station since it is in the subcarinal location. More will be described about this later.

3) Posterior mediastinal nodes: These include levels 8 and 9 which are paraesophageal and inferior pulmonary ligament nodes.

4) Anterior mediastinal nodes: These include the aortopulmonary and para-aortic nodes (levels 5 and 6).

As mentioned, level 7 or subcarinal nodes represents an important nodal station. This can be sampled by mediastinoscopy as can the other paratracheal nodes and tracheobronchial nodes, and this will be described later. However, only the anterior portion of the level 7 subcarinal node can be biopsied by mediastinoscopy and, in this sense, it represents only the tip of the iceberg.

Lymphatic System Mediastinal

Fig 11.6. Lymph node map of mediastinal (N2) and intrapulmonary (N1) nodes. 1,2,3. N2 Nodes (Mediastinal): 1-high pre/retrotracheal; 2-high paratracheal; 3-low pre/retrotracheal; 4-low paratracheal; 5-aortopulmaonary; 6-paraaortic; 7-subcranial; 8-paraesophageal; 9 pulmonary ligament; 10-hilar. N1 Nodes (Intrapulmonary): 10-hilar; 11-interlobar; 12-lobar; 13-segmental. Another classification is anterior mediastinal (5,6); posterior mediastinal (8,9); tracheobronchial (7,4,10); and paratracheal (1,2,3).

Fig 11.6. Lymph node map of mediastinal (N2) and intrapulmonary (N1) nodes. 1,2,3. N2 Nodes (Mediastinal): 1-high pre/retrotracheal; 2-high paratracheal; 3-low pre/retrotracheal; 4-low paratracheal; 5-aortopulmaonary; 6-paraaortic; 7-subcranial; 8-paraesophageal; 9 pulmonary ligament; 10-hilar. N1 Nodes (Intrapulmonary): 10-hilar; 11-interlobar; 12-lobar; 13-segmental. Another classification is anterior mediastinal (5,6); posterior mediastinal (8,9); tracheobronchial (7,4,10); and paratracheal (1,2,3).

The level N-2 nodes, if involved, means mediastinal involvement by lung carcinoma, and signifies unresectibilty. Conversely, N-1 nodes are intrapulmonary nodes and although involvement of these nodes by carcinoma implies a worse prognosis and decreased life expectancy, it does not preclude resectability. The lymphatic drainage of the right lung is ipsilateral, except for an occasional instance in which drainage to the superior mediastinum is bilateral. Drainage from the left lung to the superior mediastinum is as frequently ipsilateral as it is contralateral.

Another important concept is the "lymphatic sump of Borrie" which represents lymph nodes on each side that receive lymphatic drainage from all lobes of the corresponding lung (Fig. 11.7). The significance is that nodes in this region can be involved with lung carcinoma from any lobe of the lung on that particular side.

Fig 11.7. Sump of Borrie.

Suggested Reading

1. Brock RC. The anatomy of the bronchial tree, 2nd ed. London: Oxford University Press, 1954.

2. Corey RAS, Valentine EJ. Varying patterns of the lobar branches of the pulmonary artery. Thorax 1959; 14:267.

3. Kent EM, Blades B. The surgical anatomy of the pulmonary lobes. J Thoracic Surg 1942; 12:18.

4. Shields TW. Surgical anatomy of the lungs. In: Shields, ed. General Thoracic Surgery, 5th edition. Philadelphia: Lea and Febinger, 2000; 63-75.

The Latest Anti Aging Treatments

The Latest Anti Aging Treatments

Are You Striving To Look And Feel Youthful? Wish You Could Add 20 Years To Your Life? Discover the Secrets to a Longer, Healthier Life With This Fantastic Anti-Aging Resource. You might be feeling and looking great now, but have you ever thought about what youll feel and look like several years from now? Have you ever considered that the choices you make today directly influence how well you age?

Get My Free Ebook


Post a comment