Clavicula : the Latin term for clavicle, and the obvious root from which its English name was derived. I always thought it to be a peculiar name for the bone. Clavicula, translated directly from Latin, seems to have carried several distinct meanings:
Despite tortuous arguments I have come across from internet anatomists, none of these seem to be related to the bone in a satisfactory manner. The most popular association I’ve seen attempted is likening the shape of the clavicle to a key, often specified as an “old fashioned” key. However, I fail to see the resemblance myself.
A tendril? Maybe. It certainly more closely resembles a sinusoidal vine than a key to my eyes, though the connection still feels strained. Surely the first analogous object to come to mind when viewing a clavicle is not the tendril of a vine? Though, perhaps it was named implying the arm as a vine, with the clavicle being the tendril that anchors it to the thorax. I could see that, though it does seem to be bit of a case of post hoc rationalization.
A bar or bolt of the door, too, seems odd. Certainly it may resemble a bar morphologically, if a bit more curvaceous than one would hope for when securing a door. Functionally however, this seems to miss the mark ; while in a sense the clavicle does serve as an anchor, in doing so it facilitates the maximal range of motion of the arm. This feels in opposition to the purely immobilizing and restricting action of a door bolt.
Stepping away from our likely-unsolvable etymological mystery, I do see some personally relevant symbolism in clavicula as a key. In several ways, it has served and continues to serve as a key to my condition and my understanding of it. On a surface level, it’s often the most visibly identifiable divergence from typical anatomy to the outside observer. The appearance of the left clavicle, and in particular its approach and relationship with the manubrium, is a clear sign to an discerning observer that something isn’t quite right in the region.
Granted, this discrepancy is not overtly pathological in appearance, and follows the trend of my anatomy to present only subtle deviations from the norm on an external level. However, it is clearly apparent when attention is brought to it, and in this sense can serve as a key to identifying that a problem is present in the first place. Further analysis of the region and its kinematics upon movement of the upper limb reveals quite apparent abnormalities in the relationship of the clavicle and the manubrium at the sternoclavicular joint.
This sort of position-mediated luxation and relocation of the medial head of the clavicle, occurring in a unilateral fashion, should be a cause for pause, at the very least, for anyone investigating the pathological symptoms I presented with. It should have been a massive red flag for the litany of specialists I consulted with. However, this feature seems to have largely only been meaningful to myself. In this sense, again, the clavicle served as a key to unlocking the rabbit hole of cause-and-effect that I have been travelling down in search of answers. In turn, it also served as the key for unlocking the desire and willingness to learn, and the capacity to attempt to apply the knowledge I’ve gained in the pursuit of my own salvation, by existential necessity.
Expanding our field of view, the clavicle itself is located very near to the center of the multi-dimensional series of dominoes which I believe culminate in the manifold manifestation of my symptoms. While not the true root (that honor belongs to the rib and the manubrium, in my eyes), it does serve in a sense as the first victim, one of the first dominoes to fall. A patient zero, so to speak.
Due to the posterior positioning of the clavicular notch of the manubrium on the left side, and the resulting alteration in its relative position to the first rib, the mechanics of the sternoclavicular joint and the clavicle are altered. In a portion of the range of motion of the upper limb, the clavicle forms a lever with the first rib acting as a fulcrum, forcing the medial head of the clavicle anteriorly, luxating from the joint facet. While the connective tissue supporting the stability of joints do have a degree of elastic deformation available to them, excessive stress and stress over time does tend to result in plastic deformation, and increased laxity (this will be elaborated on in greater depth in future work). The physics of the joint are self defeating.
This alteration in kinematics of the clavicle-manubrium-rib system, in turn, compromises neurovascular structures in the region. In the anatomical space lying below the clavicle and above the first rib, the thoracic outlet, the majority of the neurovascular supply for the upper limb is routed. This includes the subclavian artery, the subclavian vein, and the brachial plexus. The altered path of motion the clavicle travels relative to the first rib appears to lead to compression of the region, which in turn leads to dysfunction of these nerves and vessels. The precise mechanisms by which this physical compression leads to dysfunction in these structures will be investigated further in future articles, but in short there are both acute manifestations of symptoms and more chronic, degenerative processes that result.
These localized pathological processes can, in turn, affect other interconnected regions, by a number of paths. Compression of a major artery or vein will invariably affect the fluid dynamics both beyond and before the point of compression. Peripheral neuroinflammation can in turn lead to the proliferation of central neuroinflammation. Compromised lymphatic ducts can lead to disturbances in immune processes. Dysfunction in one joint can lead to dysfunction in another, and often many.
While functionally I do not believe a bolt is a fair analogy to the clavicle, a connection maybe made by way of the strut. Formally, a strut is a component which primarily serves to resist longitudinal compression. In fairness, this is opposed to the more tension-resistive role of a door bolt. However, there are cases where the phrase is used a bit more liberally, as in a reinforcement strut in a garage door. As I believe I have sufficiently twisted the words to fit my narrative, let’s move on to the strut of the body: the clavicle.
The clavicle serves as an anatomical strut, ensuring that a constant distance is maintained between the sternal facet of the manubrium and the acromion of the scapula. In maintaining this fixed distance between the scapula and the axial skeleton, it ensures that glenohumeral joint is given adequate space to properly articulate and bring the arm through its exceptional range of motion without coming into conflict with chest wall.
This strut also serves as the sole bony connection between the axial and appendicular skeletons, which all other ties being comprised purely of muscle and connective tissue. In this sense, it also greatly increases the stability of what would otherwise be a fairly unstable structure, allowing for greater load-bearing capacity and more direct transfer of force to and from the thorax. Given this, it should come as no real surprise that a major alteration in the physics and function of the clavicle would translate to major alterations in the physics and function of the upper limb as a whole.
In this sense, again, we find that the clavicle is once more a key. This general concept of cascading dysfunction within the musculoskeletal system, radiating outwards from a central point, is absolutely to the understanding of my condition. Our little key makes this obvious and unambiguous in this region; the dysfunction can be seen. Travelling down the halls beyond the door it unlocks, we discover an intricated and interwoven machine, which has been thrown severely out of equilibrium.
The shoulder, itself, is not an isolated system. It too has connections separate from the clavicle, and major instability and dysfunction imparted into it by way of our tendril will in turn impart instability and dysfunction on these other connections. Which, in turn, et cetera.
Understanding this concept on an intuitive level is incredibly natural for me; I am in the meat suit. I am occupying my flesh, and I have full access to the entire arsenal the human body has developed over its long history of evolution of quantifying the state of its physical being and building and effective model thereof. I know what is wrong, the challenge however is arriving there by rational means rather than invoking some impossible-to-convey inner experience. That is the purpose and goal of this work, and that is what I intend to accomplish here.
The clavicula is certainly a key for that.