The intercostal lymph node (Figures 17: g, 18: 9) was found in only 14 of 54 cases: in 5 cases on the left side, in 7 cases on the right side, and in 2 cases on both sides. In all cases, it was found as a single lymph node.
It was found either in the 5th or 6th intercostal space, near the costovertebral joint, or directly at the 6th costovertebral joint, underneath the pleura, in the fat on the intercostal artery and vein, and on the right side, just dorsal to the azygos vein (Figure 18: h).
The size of the lymph node ranged from 2 to 7 mm.
If an intercostal lymph node is present, it usually drains some of the lymph vessels that pass through the last 6 to 8 intercostal spaces into the thoracic cavity and run cranial along the thoracic vertebrae and the M. longus colli to the cranial mediastinal lymph node. The intercostal lymph nodes also drain some of the lymph vessels from the M. subscapularis, longissimus dorsi, ileocostalis, trapezius, and rhomboideus thoracalis, as well lymph vessels from the M. latissimus dorsi, serratus ventralis, obliquus abdominis externus and internus, transversus abdominis, serratus dorsalis inspiratorius, spinalis and semispinalis dorsi and cervicis, the Mm. intercostales, the ribs and the scapula, and also the lymph vessels from the pleura, the aorta, the thoracic vertebrae, and the nervous system.
One to 3 efferent vessels emerge from the intercostal lymph node, running cranioventrally on the M. longus colli, forming networks of vessels that delimit large islands, and terminating upon draining into a cranial mediastinal lymph node (see Figures 17 and 18).