Peripheral Course of Sensory Nerves Supplying Arteries of Lower Extremity

Abstract

Lumbar sympathetic gangliectomy abolishes the reflex vascular spasm, the central feature of Raynaud's disease. The immediate relief of the accompanying pain is so striking that it has led clinical observers to conclude that some type of sensory nerve to the lower extremity is sectioned in the course of the sympathectomy. This view is strengthened by the experiments of Johnson 1 and of Kuntz and Farnsworth, 2 which demonstrated that certain of the dorsal root components of the lower dorsal and upper lumbar spinal nerves pass to the lumbosacral sympathetic trunks and are distributed from them to the lumbosacral plexus.

During the course of experiments in arterial visualization, we noted that cats under sodium amytal anesthesia reacted in a characteristic manner when a concentrated solution of sodium iodide was injected into the femoral artery. The entire body stiffened with the legs straining at the leashes; hyperpnea; dilatation of the pupils; tossing of the head accompanied by vocalization, the outcry possessing sometimes a plaintive note and sometimes a note of anger. This reaction of the anesthetized animal is identical with the external manifestation of the perception of acute pain during conscious states. It is not accompanied by subjective perception of pain, for Woodworth and Sherrington 3 showed that such “pseud-affective” reactions persist after ablation of the cerebrum and diencephalon. It results, we may presume, from afferent impulses which, were the function of the brain intact, would evoke “pain”.

We made use of this “pseud-affective” reaction of the amytalized cat in an attempt to determine the course and termination of the “pain” fibers stimulated by the intra-arterial injection of the sodium iodide. When the iodide is confined to the trunk artery by the ligation of its branches, no reaction occurs.