Ultra High-frequency Ultrasound of Fascicles in the Median Nerve at the Wrist

Introduction: An ultra high-frequency (70 MHz) ultrasound device has recently been approved for human use. This study was conducted to determine if this device facilitates counting of fascicles within the median nerve at the wrist. Methods: Twenty healthy volunteers underwent imaging of the median nerve at the wrist bilaterally. The number of fascicles in each nerve was counted by two independent raters. Results: The mean fascicle number was 22.68. Correlation was strong between the two raters (r = 0.68, p < 0.001). Age, sex, body mass index, and nerve area did not predict fascicle number. Those with bifid median nerves and persistent median arteries had lower fascicle density than those without anatomic anomalies (1.79 vs. 2.29, p = 0.01). Discussion: Fascicles within the median nerve at the wrist can be readily imaged. Ultra high- frequency ultrasound technology may be informative in a variety of disorders affecting the peripheral nervous system.