THE RANGE OF CONDUCTION VELOCITY IN NORMAL MOTOR NERVE FIBRES TO THE SMALL MUSCLES OF THE HAND AND FOOT

Open Access
Publisher Website
Google Scholar
Abstract
Following 180 observations on 150 subjects it was found that the maximum conduction velocity in normal motor nerve fibers to some small muscles in the foot was significantly less than that in the hand. The average length of nerve stimulated was 30 cm. In the upper extremity the median or ulnar nerve was used and observations made of the abductor pollicis brevis, abductor digiti minimi and the first dorsal interosseous. In the lower extremity the lateral or medial popliteal nerve was stimulated proximally and the anterior or posterior tibial nerve stimulated distally with observation of the extensor digitorum brevis and the abductor hallucis. The extensor, in this testing, showed a greater maximum conduction velocity than the abductor because the fibers supplying it are likely to be of greater diameter. The lower conduction velocity in the foot as compared to the hand is explained on the basis of fibers with smaller diameter and a conduction rate 30-40% below the maximum. The extremely low values for nerve conduction found in some patients with lower motor neuron lesions cannot only be due to slow conduction in normal surviving fibers but must be due to abnormal nerve function related to structural and/or metabolic changes.

This publication has 6 references indexed in Scilit: