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Pain
Referred to Somatic Structures
Neurophysiological
observations support clinical experience showing that angina pectoris
is most commonly felt in the proximal and axial regions of the
left arm and chest and less frequently sensed further down the
arm (Bennet
et al, 1966; Sampson
and Cheitlin, 1971; Sylven,
1989).
In animal
studies, stimulating cardiac sympathetic afferent fibers strongly
excites a majority of the spinothalamic tract cells with proximal
somatic receptor fields, but only weakly excites a small portion
of the cells with distal somatic input (Hobbs
et al, 1992). Thus, a highly significant relationship exists
between cells with excitatory visceral input and proximal axial
fields.
Angina pectoris
often mimics muscle pain in that both of these types of pain are
described as deep, diffuse, dull and suffering. In contrast, cutaneous
pain is usually sharp and localized. Similarities between muscle
pain and cardiac pain are shown in patients suffering from angina
pectoris (Lewis, 1942).
Patients compared
pain provoked by a hypertonic saline solution injected into the
paraspinal muscles of the left eighth cervical or first thoracic
spinal segment with pain that was evoked during angina pectoris.
These patients observed that the onset, continuation, segmental
localization and character very closely mimicked anginal pectoris
(Lewis, 1942).
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