The whole concept of fluid mechanics is that the further away we get from the heart, the harder it is for us to pump blood and deliver oxygen to the muscles and tissues. In osteopathy, our focus is to make sure that everything up the chain is released, that we have unimpeded movement of all of the body's vital fluids.
Imagine a garden hose, if there is a kink in the hose, the fluid does not move and pressure builds up behind the kink causing the hose to potentially burst, or if the obstruction is only partial, an increase in pressure of the water coming out at the end of the hose. This would be similar to how the arteries and veins of the human body work. A number of complications can arise from obstructions including, but not limited to, a pooling of fluid in the tissues.
Pooling of fluid in the body is an indicator to an osteopathic practitioner that the fluid dynamics of the body are altered and from here we begin to search for that "kink in the hose".
Similarly, obstructions are not limited to the fluids of the body but can also affect the nervous system and how well the nerves conduct. For example, if you lay on your arm for a period of time you may find that your hand or arm has "gone to sleep". This pins and needles feeling that you get is the manifestation of a change in innervation to the area. An indication that you may want to see a practitioner would be if you are experiencing extended periods of numbness or tingling in the hands or feet, as this could be a symptom of an obstruction to the nerves proper conduction.