THE CONTRIBUTION OF ISCHEMIA AND DEFORMATION TO THE CONDUCTION BLOCK GENERATED BY COMPRESSION OF THE CAT SCIATIC-NERVE

The pattern of conduction block induced in cat peripheral nerve by compression has been investigated electrophysiologically by recording unitary action potentials. A degree of compression, associated with chronic compression disorders in man, was applied to the cat sciatic nerve and resulted in a conduction block typified by early failure of the slow conducting myelinated axons. By contrast, a greater degree of compression, a degree more likely to result in acute compression lesions, produced a different pattern of effect, inducing early conduction failure in the fast conducting myelinated axons. These results are related to earlier studies which have shown that nerve deformation during compression has a differential action upon fast myelinated axons, while nerve ischaemia has a differential action upon slow myelinated axons.