Sciatic nerve motor conduction velocity study.

Electrophysiological investigation of human peripheral nerve has been extensively conducted over the past years. Motor conduction velocity determination has become a standard laboratory procedure, and its value in the diagnosis and localization of peripheral nerve lesions is well recognized. The method involves the application of an electrical stimulus on the skin overlying the nerve trunk with a surface electrode and the recording of muscle potential from a small muscle innervated by a terminal branch of the nerve. Deep-seated nerves are inaccessible to surface-stimulating electrodes. This procedure is, therefore, limited to a few superficially situated nerves. The latency and waveform of evoked muscle potential recorded from a big muscle vary with the nature and placement of recording electrodes, and their interpretation can at times be quite difficult. Certain methods (Arrigo, Cosi, and Savoldi, 1962; Gassel, 1963; Gassel and Diamantopoulos, 1964; Gassel and Trojaborg, 1964; Downie and Scott, 1964) to determine the conduction velocity of deep-seated nerves and those supplying big muscles have been introduced; however, they have not met with wide acceptance. The purpose of this study is therefore to establish a method for the determination of motor nerve conduction velocity of deep-seated nerve and to evaluate the problem of recording muscle potential from a group of big muscles. Sciatic nerve is chosen as the subject for two reasons: 1 There is no vital structure nearby that may be damaged by a probing, stimulating electrode. 2 The motor conduction velocity of its terminal branches has been established by other workers (Hodes, Larrabee, and German, 1948; Carpendale, 1956; Henriksen, 1956; Thomas, Sears, and Gilliatt, 1959; Johnson and Olsen, 1960; Skillman, Johnson, Hamwi, and Driskill, 1961; Arrigo et al., 1962; Mavor and Libman, 1962; Mayer, 1963; Angel and Alston, 1964; Gassel and Trojaborg, 1964; Mawdsley