The eleventh rib is the first rib that does not articulate with the sternum in any way. The eleventh rib has only one articulation with the facet of the eleventh thoracic vertebrae. The eleventh rib is highly invested in musculature and displays marked mobility that is often checked by the musculature that attaches on its inferior surface.
The muscles that attach to the eleventh rib are: serratus posterior inferior, iliocostalis thoracis, iliocostalis lumborum, latissimus dorsi (via the thoracolumbar fascia), external oblique, transverse abdominis (this is dependent on the source – Marion Clark notes this attachment), levator costae, internal intercostal, and external intercostal. The pleura is also connected to the internal surface of the eleventh rib. Due to the shape, position, and muscular attachments of the eleventh rib it can be looked at as a fulcrum for the ribs above it during respiration as the muscles attaching to the inferior surface fix this rib as the other ones rise during inhalation. The eleventh rib primarily displays a caliper type motion in the transverse plane (there are other possible movements but this is primary).
The nerves associated with the eleventh rib are: the anterior and posterior divisions of the eleventh thoracic nerve, the eleventh intercostal nerve, the sympathetic chain ganglia, the eleventh thoracic sympathetic ganglion, the recurrent meningeal nerve, and the lesser splanchic nerve.
The circulatory structures associated with the eleventh rib are: the intercostal artery and vein, the mediastinal artery and vein, the azygos and hemiazygos vein, the bronchomediastinal lymphatic duct, and the thoracic lymphatic duct. As with the eighth, ninth ribs, and tenth I will suggest that the connection of the eleventh rib with the diaphragm also has the ability to effect the descending aorta, the inferior vena cava, the phrenic arteries and veins, as well as the superior mesenteric artery.
The eleventh rib is physically related with the spleen on the left and the right side is in relation with the liver. For some people the upper part of the kidney can also be in relation with the eleventh rib.
Through sympathetic nervous system connections the eleventh rib is implicated in conditions of the bowel, kidney, liver, spleen, and ovaries. Pseudoappendicitis is related to the eleventh rib via the lesser splanchic nerves contribution to the celiac ganglia as it influences the ileum (pseudoappendicitis being relatable to acute inflammation of the ileum). The abdominal pain that can be associated with pseudoappendicits as well as any other pain that may be located at McBurney’s Point is related to the eleventh rib (keep in mind that the multiple nerve paths associated with McBurney’s Point are the reason that it is not the final say in diagnosing acute appendicitis, just a very likely indicator).
So what is really going on with all of these rib lesions and the associated conditions? Does the rib lesion really CAUSE the condition? The answer is very Osteopathic…MAYBE. The best way to attempt to understand it is the principle that structure and function are reciprocally related. If the eleventh rib is in lesion it ensures that related conditions have the ability to exist via altered vasomotion, mechanical stress, altered pressure gradients in the body cavities, altered nervous system communication as well as other alterations in function due to the structural lesion. Does one cause the other? Yes…and no. One may be the cause and the other the reflex but once present they both cause one another to stay through reflex loops. Reflex loops will be discussed in the future on this blog, just know that reflex loops are essentially the reason that nothing in Osteopathy is idiopathic (it is through reflex loops that everything makes sense to an Osteopath where it has no understandable etiology for other practitioners).