부산대학교 도서관

ObjectiveThe recording position for conduction study of the inferior calcaneal nerve (ICN) that was used previously was the midpoint of the line joining the sole of the foot with the tip of the lateral malleolus. This could be over the calcaneus but not over abductor digiti minimi (ADM) muscle. We aimed to establish an optimal recording position for the electrode to for study ICN conduction. Methods We studied both the lower limbs of 20 healthy subjects (11 men and 9 women). Two active recording positions for ICN conduction were evaluated using electrophysiological and ultrasonographic examinations. The first active recording position (A) was over the midpoint of the line joining the tip of lateral malleolus and the sole. The second active recording position (B) was over the midpoint of the ADM. This was determined by applying the probe along the bisection of a line joining the lateral process of the calcaneal tuberosity and the tuberosity of the fifth metatarsal bone. Ultrasonograms and compound muscle action potentials (CMAP) were obtained from positions A and B and analyzed. Results Ultrasonographic examination revealed no muscle fibers in position A. Position B was located 1.3 ± 0.3 cm anterior and 1.2 ± 0.2 cm inferior to A. The amplitudes of CMAPs (14.2 ± 3.2 mV) recorded over position B were significantly greater than those from A (13.7 ± 3.5 mV). Conclusions Although we obtained an inferior calcaneal motor response from position A, it seemed less adequate as no muscle fibers were present on ultrasonography. Position B was a more optimal active recording position to study ICN conduction than A.