2. A Continuous Exchange
Posted on 05. Jun, 2010 by Anatomy Links in Anatomical Connections
For a better understanding please read “Physical Inter-Organ Connections” before reading this entry.
Either fixed and/or not fixed, all of our organs physically relate to their neighboring organs. Because they do, because they all connect and touch, they constantly exchange influence.
Without end (day and night) our muscles, bones, deep fasciae, nerves and other organs exchange mechanical force [?] and nerve impulses.
Externally and internally originating forces affecting our organs are passed to connecting organs and translated to afferent nerve impulses. Either obscure to us or noticeable, the afferent impulses are answered by efferent impulses, in turn generating obvious or subtle internally originating mechanical forces. The purpose of this continuous give and take between organs is generating motion, maintaining posture, providing joint stability, circulating blood, maintaining homeostasis, and so on.
Although the ongoing exchange pertains to all our body parts, not all of them trade the same kind of influence. Depending on which organs connect and how (fixed or not fixed), they trade only force, or trade force and nerve impulses.
Healthy fixed-connections enable the inter-organ exchange of both force and nerve impulses. In regard to force, all organs with a fixed relationship partake in the force-shuffle. Ligaments and bones, joint capsules and ligament, bones and muscles, muscles and deep fascia; all fixed related organs exchange force. Even nerves, arteries and veins, and the organs they are bound with [?] participate in this ongoing correspondence of physical energy. Unlike all other securely anchored organs, the connecting peripheral nerves and muscles and peripheral nerves and blood vessels, exchange both force and nerve impulses [?]. The hamstring muscles and the sciatic nerve, for example, exchange both. Just like the femoral artery and the femoral nerve.
Healthy not-fixed-connections only exchange force. Unlike the fixed connections, however, they are designed to limit the inter-organ trade of shear and pull. The loose inter-organ bonds are perfectly suited to control the amount of force travelling between relating organs. The connection between the iliotibial band and the vastus lateralis muscle for example, is built to limit their correspondence. The same is true for all other not fixed bonds. The not fixed connections between organs and crossing peripheral nerves and blood vessels are designed to do the same. Also synovial joints, not fixed connections between individual bones, are assembled to control the exchange of force between relating parts.
Food for Thought:
With the previous information in mind, what happens to its fixed relations when an organ goes through a character change, for example a change in tonus, pliability, length, etc?
And, what happens to its fixed relations when an organ passes on an abnormal amount of force or an abnormal number of nerve impulses?
And finally, what happens when a not fixed connection adheres and loses its mobility or range of movement?
1. Physical Inter-Organ Connections
Posted on 10. Feb, 2010 by Anatomy Links in Anatomical Connections
“The toe bone connected to the heel bone, the heel bone connected to the foot bone, the foot bone connected to the leg bone, the leg bone connected to the knee bone, the knee bone …”
Like the song “Dry Bones” by James Weldon Johnson implies, the bodies’ bones connect with one another. What James Johnson did not sing about is that not only bones but all our organs connect. Our arteries, bones, deep fasciae, ligaments, muscles, peripheral nerves, and all other organs physically connect to form the human body.
Although most physical inter-organ connections have unique features based on which organs connect and where the connection is located in the body, we can divide them into two large groups; the physical fixed connections and the physical not fixed connections.
The fixed connections are, like their name implies, tightly anchored. They do not allow – or are not supposed to allow – any movement between connecting parts. To guarantee a strong link, the fixed connections are mainly established through the organ-unique connective tissues that invest and surround them. For example, the epineurium, perineurium and endoneurium of peripheral nerves are continuous with the meninges (the dura, arachnoid, and pia mater) surrounding the CNS. In the periphery, the nerves are anchored to the muscles through the “same” epineurium, perineurium and endoneurium. Bones and muscles also connect with one another. At a muscular attachment site, the bone’s periosteum is continuous with the epitenon and endotenon of the muscular tendon. For extra strength the tendon’s collagen bundles are anchored deep into the (cortical) bone. From a functional perspective, the fixed union – no freedom or slack between connecting parts whatsoever – is a requirement for health and proper function.
Opposed to the fixed links, the not fixed connections are not tightly anchored. They do allow – or are supposed to allow – at least some movement between connecting parts. The not fixed connections are generally established through interposed loose connective tissue. Arteries, veins and peripheral nerves, for example, loosely connect with muscles and the other organs they cross through a thin layer of loose connective tissue. Interposed loose connective tissue also ensures some movement between neighboring muscles. Of all not fixed connections only the bone-bone links (also known as synovial articulations or joints) are not established through loose connective tissue. Unlike other not fixed bonds these joints are established through interposed synovial fluid. From a functional perspective, the “free” or not fixed relationship – a certain degree of kinetic freedom or slack between connecting parts – is a requirement for health and proper function.