"PINS AND NEEDLES"OBSERVATIONS ON SOME OF THE SENSATIONS AROUSED IN A LIMB BY THE APPLICATION OF PRESSURE

Abstract

Observa-tions are reported on the subjective sensation, their accurate description, the moment of occurrence and disappearance, and associated vasomotor states produced by inflation of a cuff of a sphymomonometer to 150 mm. Hg fastened about the arm or forearm. Pressure was maintained for variable lengths of time and symptoms following its sudden release described in 7 normal subjects and 9 patients with various pathologic changes involving one upper limb. The sensations produced are named and defined. They are: (1) com- pression tingling and (2) "velvety numbness" both occurring at different times during the compression and (3) "release pricking" which occurs after the compression is released. On the basis of their results in which the effects of varying many local conditions of compression, the distribution of the sensation in the various nerve sensory areas, effects of repeated compressions and comparison with patients with various neurological lesions, it was concluded that the site of the "compression" tingling was the nerve trunk under the compression cuff and that the mechanism was stimulation by asphyxia of touch fibers. On the basis of many similar modifications of technique described and on the similarity of the behavior of reactive hyperemia following compression to the phenomena of "release pricking", the authors conclude that this sensation is conveyed mainly by somatic pain fibers and is due to the stimulation of the peripheral nerve endings in the area in which it is felt. This stimulation is probably occasioned by the removal, from the tissue spaces around the nerve endings, of a chemical substance which accumulates there during the period of circulatory depression.