The first of the false ribs…how is that? The eighth rib, and those below, are considered false as they do not articulate directly with the sternum but with the common costal cartilage. As a result of the attachment to the costal cartilage the eighth rib is fairly mobile (as are the ribs below it – until you get to the eleventh and twelfth ribs). The movement characteristics can be described as a bucket handle, or upwards and outwards on inhalation and downwards and inwards on inhalation.
The muscles that attach to the eighth rib are: the diapragm, internal abdominal oblique, external abdominal oblique, transverse abdominis, serratus anterior, iliocostalis thoracis, iliocostalis lumborum, internal intercostal, and external intercostal.
The nerves associated with the eighth rib are: the eighth thoracic nerve with both anterior and posterior divisions, the sympathetic chain ganglia, the eighth thoracic sympathetic ganglion, the greater splanchic nerve, and the recurrent meningeal nerve.
The circulatory structures associated with the eighth rib are: the intercostal artery and vein, the azygos vein, the accessory hemiazygos vein, the hemiazygos vein, mediastinal artery and vein, thoracic lymphatic duct, and bronchomediastinal lymphatic duct. Due to the connection with the diaphragm I will suggest that the eighth rib also has mechanical possibilities to have an effect on the phrenic arteries and veins, the descending aorta, the inferior vena cava, as well as much of the celiac trunk. It is also important to consider that much of the influence of a lesion of the eighth rib may be noted through vaso-motor connections (such as in the celiac trunk).
This is the area of the ribs where we can really start speaking about the abdominal viscera. Through nervous connection the eighth rib is in contact with the stomach, liver, gall bladder, spleen, pancreas, and parts of the duodenum. Some of these connections may vary depending on your resources but when you are dealing with the eighth rib you should at least consider them. The primary connections here are sympathetic in nature and, as such, if there is increased sympathetic tone there will be a decrease in digestive functions. All of the circulatory issues possible with other rib lesions are shared with a lesion of the eighth rib.
Looking farther than just the direct connections to the eighth rib I am left to wonder what the effects to the phrenic nerve (C3-C5) would be with a lesion of the eighth rib or any other that has influence over the diaphragm? My assumption is that there is a possibility of reflexive lesioning in the lower cervical unit due to the motor tone through the phrenic nerve. At the same time there is the possibility that a lesion to the lower cervical unit will alter the motor tone to the diaphragm and the reflex will be a rib lesion. Maybe the Operator will not be able to truly correct the eighth rib until they correct the lower cervical unit? This thought process seems to provide affirmation for the Osteopathic principle that the body is a single integrated unit of structure and function (mind, body, and spirit).