I have a confession to make, the inguinal ligament was just a meaningless name to me until I was in my second year at the CAO. My previous education had not provided me with a meaningful explanation or understanding of what the inguinal ligament is or how important it is to the function of the lower body. In my writing I endeavor to show that all parts of the body are important while placing focus on a specific area to help illuminate functional relationships which was driven home to me when I learned more about the inguinal ligament. So, for whatever it is worth, I will write about some of the functional relationships of the inguinal ligament.
First I will write the sentence that turned the light bulb on for me – the inguinal ligament is the lower free border of the external abdominal oblique. That could be a sentence in any anatomy text book which is read by students around the world and remembered by all of them…yet somehow still be absolutely meaningless. The fact that the inguinal ligament is the lower free border of the external abdominal oblique automatically connects the innominate directly to ribs 5-12 (with related connection through the ribs to the diaphragm), the serratus anterior (and the scapula), and the latissimus dorsi (and the humerus).
Before I wander too far off I want to highlight the relationships between the fluid vessels and nerves to the lower limb. From medial to lateral we find the femoral vein, femoral artery, then the femoral nerve. The spermatic cord (in men) or the round ligament (in women) begins forming at the deep inguinal ring, runs through the inguinal canal, then exits through the superficial inguinal ring. Attached (surrounding) to the spermatic cord is the cremaster muscle which controls the position of the testicles in males so that the temperature of them may be regulated through proximity to the pelvic cavity. There is also another set of interesting relationships between the fluid vessels and the muscles that pass inferior to them – the femoral vein is medial and superior to the psoas (which is not particularly wide at this point) as well as lateral and superior to pectineus, the femoral artery is superior to the psoas, and the femoral nerve is essentially superior to the iliacus (which is quite broad at this point). The relationship between the psoas and the femoral artery and vein suggest that the mechanical function/position of the lumbar spine will alter the compression/tension relationship from the lumbar spine to the lesser trochanter of the femur which may have a major effect on these fluid vessels by altering the space they occupy between the psoas and the inguinal ligament. The interesting part here is that the femoral vein is the most medial structure and has more potential space such that it may expand medially towards the femoral ring (which, according to some sources I have come across contains Cloquet’s node – a lymphatic passage) which is superior to the pectineus.
As I suggested with the title, these are wandering thoughts! While going through them the world has started to spin a little bit as all of these connections can end up looking like a mess of tangled wires when viewed from too close of a position. I find that the common view of anatomy that involves separating structures for naming purposes to be a gift and a curse – the human mind seems to require that for the purpose of understanding while at the same time limiting the ability to see how these structures blend so seamlessly together as a single unit.
Back to some anatomical thoughts! The position of the inguinal ligament proper as being entirely connected to the innominate leads to connections through the entire lower limb, the entire pelvis (including the sacrum), and (as discussed briefly above) the upper body (both directly and indirectly via the external abdominal oblique). So what might any of this end up meaning? The iguinal ligament may be related to any and all fluid issues (active/supply or passive/drainage) in the lower limb as well as directly to neurological issues on the anterior portion of the thigh. Taking in to consideration that much of the supply and pretty much all of the drainage to the lower limb runs under (posterior really) the inguinal ligament (in to the pelvis/abdomen) as well as all of the mechanical connections it has, the Operator is required to be at least intellectually willing to inspect function along the lines of the aforementioned connections if there is not a local lesion found with a supply/drainage issue in the lower limb.
These thoughts, for me, begin to serve my mind in my willingness to understand the reality that the location of a symptom is legitimately a result of alterations in coordination of soft and hard tissue that may be very distant from the site of the symptom. It is imperative that anyone that is truly looking to help people with health concerns be at least willing to think through these possibilities (my bias tells me that it is imperative to use these thoughts to make meaningful adjustments to allow a patient’s body to work the way it is supposed to work). As an interesting thought – what if a male has an issue with their sperm count (the spermatic cord travels through the inguinal ring as well as being surrounded by the cremaster muscle) and their is not a MAJOR pelvic lesion? It would be a fools game to say that is just the way of things without at least inspecting the external abdominal obliques, ribs 5-12 (and the diaphragm), the lattisimus dorsi (and the humerus), the serratus anterior (and the scapula), the lumbar spine (with the psoas and the genitofemoral nerve), and the femur (with all of its muscular attachments) as any of these structures may send trouble to the inguinal ligament without the presence of a clear pelvic lesion. We must be willing to look at the person as an entire unit or else we may miss the solution.