I remember hearing a cardiologist once say that the cardiovascular system has nothing to do with the musculoskeletal system. I have also heard as much from other specialties during my medical training. This idea of separating systems has become so ingrained in our mentalities, that patients often ask if their problem is caused by a muscle, joint, nerve, tendon, etc. The problem with this mentality is that we are acting as if things actually do act in isolation from each other. In reality, they do not.
We separate systems in order to simplify the complexity of the human body. It is to help us understand more clearly how the body operates. It seems that by making these separations, we have actually forgotten that the body does not work function as a series of systems that act independently of each other. For example, running or exercising is an example of the musculoskeletal system having a strong effect on the cardiovascular system. It does not only affect the cardiovascular system, but every other system such as the digestive system changes, the renal system, and nervous systems respond to the demands placed by the musculoskeletal system. Even the skin will change to effects front he musculoskeletal system. We also know that pain can have an effect on blood pressure. Therefore it is easy to see that the musculoskeletal system absolutely has an effect on the cardiovascular system.
There are also viscero-somatic reflexes or somato-visceral reflexes. This means that an irritated organ can such as an inflamed appendix will reflexively produce musculoskeletal changes associated with the diseased tissue. At the same time, problems in bones, muscles, and joints can have an effect on an associated organ. When you look at this more closely, it really is just the same thing.
Perhaps we should look at things differently. Imagine if you did not have your preconceived notion that bones and muscles are not organs because they are. So if you stop looking at bones and muscles as being separate and their only purpose being purely for support, then you realize all act in concert. All I am stating is that the body is in constant communication. All organs communicate with each other to produce the most appropriate responses to what is currently happening in the body and the environment.
When a patient asks if a problem is caused by a muscle, joint, tendon, or nerve, it is a question that shows a misunderstanding of the human body. A muscle does not simply tighten and become painful in isolation. It is usually responding to a problem in an associated joint, connective tissue called fascia, or an underlying organ. If there is a problem, the nervous system also makes the area and muscle more hypersensitive. Otherwise there would not be pain. Pain may then have a change in digestion by up-regulating the sympathetic nervous system and have an effect on the cardiovascular system by changing blood pressure. None of these things act in isolation but are acting together, therefore, it is impossible to answer this question with anything other than “yes” to all.
To consider that body systems are isolated entities that act independently of each other is quite arrogant actually. In addition, it provides an inconsistent view on how the body operates. To suggest that certain systems influence each other while others have nothing to do with each other is not in line with what we observe happens on a daily basis with the human body. Furthermore, it can help us understand why influencing a tissue or structure can produce changes in other structures and systems.