Pain Projection, Segmental Access and Sclerotomes
In any kind of irritation of a somatic afferent nerve somewhere along its course there is a projection of all sensations (including pain) to that part of the body where the irritated nerve is coming from. A projection of the subjective pain sensation derived from an organ is very specific for each organ as are the so-called “Head’s zones”. Knowledge of these conditions is very helpful in recognizing possible causes of a pain, whose origin need not always be situated in the periphery of the nerve. A very suitable object for demonstration of these circumstances is phantom pain. Here, irritation of a nerve (or some specific pathway) will cause a pain projection to parts of the body (e.g. lower leg) which are not existing any more. This example may also be used to state that pain will only be sensed if the relation of afferent somatic and sympathetic influx to the brain is disturbed. After restoring the normal relation, the patient will be free of pain.
KeywordsNerve Block None None Kind Permission Geniculate Ganglion Phantom Pain
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