How and why we feel pain is very complex. When there is damage to the body, sensory nerves in that area are stimulated to send messages to the brain that something unusual has happened. The brain responds unconsciously to these messages, i.e., we don’t have any direct control over it.
- A high level of nerve stimulation, for example when we touch something hot or sharp and withdraw our hand quickly, or when there is damage to a body tissue such as when an intervertebral disc prolapses, or a muscle is torn;
- Our mood, whether we are tense, agitated, anxious, relaxed, and so on, which is why, for example, we are more susceptible to pain when stressed, and why worrying about a pain can make it feel worse;
- Memories of previous similar stimulation and what it meant at the time, which is why old problems can seem to come back, and why blindfolding someone and telling them they will feel a sharp pain when you prick them with a needle, then touching them with, say, a pencil, can result in them feeling pain until they see what it really was you were using.
Based on these three influences the brain makes us feel more or less pain. Pain, therefore, is the result of how the stimulus is perceived and interpreted by the brain, rather than just the simple stimulation of nerves.
With acute conditions, i.e., those that are intense and severe and usually caused suddenly, in addition to pain, other body reactions occur in an attempt to minimise potential further harm. This can involve increased muscle tension or spasm to prevent movement; our actions are restricted and we may hold ourselves in an abnormal position to avoid putting stress on the injured tissue.
The other main response to injury is inflammation, where the tissue becomes swollen, red, and hot due to increased blood flow into the area and local chemical reactions. This also increases the sensitivity of the nerves making it feel more painful.
In the short term these responses help to prevent further injury and harm, but if they continue, muscles can become shortened, some movements become stiff and restricted, and this can make the area vulnerable to further strain or put stress on more distant part of the body.
Most osteopathic techniques, at least in part, attempt to persuade the unconscious brain to ‘relax’ its protective response, allowing the body to move more freely. This in turn enhances the recovery from injury. More direct stretching also stimulates the healthy repair of tissues, and reduces the effects of shortening of tissues that have been held in a state of increased tension. In addition, gentle hands-on stimulation of an area can ‘persuade’ the brain that it doesn’t have to respond to all impulses from the area with pain, spasm and inflammation. This allows the area to return to normal levels of response.
Pain is ultimately only the conscious part of nature’s defence system. Much happens unconsciously. The primary purpose of the unpleasant experience of pain is to ensure that we change our behaviour to minimise the risk of further harm. So if it hurts when we bend or sit, the unconscious brain is telling us ‘don’t bend’, ‘don’t sit’. Of course we have the conscious choice of whether to respond to these messages. We also have the capacity up to a point to ignore these messages – this may be unwise!