Deep somatic pain

As its name implies, deep somatic pain is generated in deep body structures, such as the periosteum, muscles, tendons, joints, and blood vessels. This type of pain is more diffuse than cutaneous pain. It may be elicited by strong pressure, ischemia, and tissue damage. 

Tissue ischemia. When blood flow to a tissue is decreased or interrupted, the tissue becomes painful within a few minutes. In fact, the greater the rate of metabolism in the tissue, the more rapid is the onset of pain. The causes of pain due to tissue ischemia include  

The lactic acid and other noxious chemicals stimulate polymodal nociceptors. 

Muscle spasm. The pain induced by muscle spasm results partially from the direct effect of tissue distortion on mechanical nociceptors. Muscle spasm also causes tissue ischemia. The increased muscle tension compresses blood vessels and decreases blood flow. Furthermore, the increased rate of metabolism associated with the spasm exacerbates the ischemia. As discussed earlier, ischemia leads to stimulation of polymodal nociceptors. 

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A distinction can be made between visceral pains, which originate in the intestines, and somatic pains, which can be localised on the skin, in muscles, connective tissue, bones and joints. Visceral pain is duU and resembles those reactions, which accompany deep pain. 

Somatic pain is subdivided into deep pain, which often carmot be precisely locahsed and spreads into the surroundings, and surface pain, which can generally be weU localised. The latter may be further subdivided into the initial pain, which normally induces a reflexive flight reaction (like the pulling away of a finger from a hot cooker plate), is easily localised, and rapidly abates after the end of the stimulation, whereas the second type of surface pain appears after a short interval as duU and biuriitigs it is more difficult to localise and subsides only more slowly. 

Somatic pain responds well to NSAIDs and narcotics. Visceral pain, deep and poorly localized, caused by irritation of the serous or distension or ischemic tissue (for example pain associated with nephrolithiasis or pancreatitis) responds better to narcotics. In some cases, however, the narcotics themselves can exacerbate the problem (for example in case of bile duct obstruction). Neuropathic pain is characterized by excruciating burning pain, and is frequently associated with hypersensitivity. It maybe more responsive to anticonvulsants and antidepressants than to opioids. 

On examination, the left buttocks was lender to palpation and there were tender points at the mid-pole of the sacrum on the lateral border and one deep to the gluteus maximus, where a lense piriformis could be palpated. There was a unilateral sacral flexion (sacral shear) present on the left. No lumbar somatic dysfunctions were present. There was mild tenderness at the sciatic notch of the ischium. Deep tendon reflexes were normal and muscle strength of the ihigh was normal. There was some pain on internal rotation and adduction of the left hip. 

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