On to the sixth rib. Finally time to stop talking just about the heart and lungs! Now we get in to the liver and stomach.
The sixth rib displays longer costal cartilage at the sternal end with a more acute angle than those above it. The interspace is not as wide as the ribs above (the interspaces slowly decrease from the third rib downwards).
The muscles associated with the sixth rib are: serratus anterior, rectus abdominis, external oblique, external intercostal, internal intercostal, iliocostalis cervicis, and iliocostalis thoracis. Due to the movement potentials of the muscles attached to the sixth rib, specific corrections are likely going to require slightly different approaches. Both the long lever and the short lever are still available to the Operator but they must pay attention to the oblique characteristic of the sixth rib.
The nerves associated with the sixth rib are: the anterior and posterior divisions of the sixth thoracic nerve, the sixth intercostal nerve, the sympathetic chain ganglia, the sixth thoracic sympathetic ganglion, the greater splanchic nerve, and the recurrent meningeal nerve.
The circulatory structures associated with the sixth rib are: the intercostal artery and vein (both the posterior and anterior branch), mediastinal artery, the azygos and accessory hemiazygos vein, mediastinal vein, pericardial vein, bronchomediastinal lymphatic duct, and the thoracic lymphatic duct.
I know I said we were done talking about the heart and lungs…but the pleura does attach to the sixth rib and it also lays over the heart. Considering the mechanical attachments of the sixth rib to the pleura, heart, and lungs a lesion of the sixth still has the ability to cause issues for these structures.
The association of the sixth rib with the greater splanchic nerve as well as the sixth thoracic sympathetic ganglion allow for alteration of nervous tone to the stomach and liver as they are both fed by the aforementioned nerves. If there is an alteration in the nervous tone the effects to the stomach and liver may be seen in altered motor tone (more or less peristalsis), altered vaso-motor tone (too much or too little blood in/out), altered mucosal secretion (if the lesion is irritating), and altered trophicity (an accumulation of nutrients or a deficiency depending on the way the lesion effects the previously discussed processes). As the nerves associated with the sixth rib have been discussed it is important to keep in mind the fields of influence to search for alterations in function or appearance.
I guess I could keep these posts shorter by saying that whatever muscular, nervous, and circulatory structures are associated with the part in question will all be affected by a lesion…too bad that isn’t instructive enough. More writing for me!
It should be clear by now that if a rib is inhaled or exhaled that the associated structures will display altered function. Ribs are very good at exciting the sympathetic chain as well as blocking fluid flow in the thorax. We will keep exploring the specific relationships to conditions at each rib as we delve in to the seventh rib and onwards.