Objectives:
Although electroneuro- and electromyography are still leading diagnostic methods for investigation of peripheral nerves function, they do not provide information regarding their morphology. This study was conducted to evaluate the suitability of ultrasonography in visualization of median nerve in healthy volunteers.
Methods:
Twenty-five asymptomatic volunteers (16 women and 9 men) have participated in this study, age ranging from 2068 years.
Device used was Aloka Prosound Alpha10 Premier with 13MHz probe, using custom preset for musculo-skeletal sonography. Following dimensions of median nerve at the level of pisiform bone were measured bilaterally: cross-sectional area (CSA), circumference, longer and shorter radius. Subsequently, using latter values, flattening ratio was calculated.
Examinees' height was measured and handedness ascertained. Additional epidemiological data taken was the average daily time that individuals spent working on a personal computer as a possible factor for compression of the nerve in examinee's dominant hand.
Results:
Median nerve was easily depicted in all of the participants as well as the surrounding soft-tissue structures. Average CSA of median nerve was 9.67 mm2 (range 5–15 mm2, with standard deviation of 2.4 mm). Mean flattening-ratio (FR) (longer radius/ shorter radius) was 4.18, ranging from 2.16 to 5.92.
Median height was 173.8 cm and only one subject was left-handed while the others (96%) were right hand dominant. Average daily time spent working on a personal computer (total average of 2.96 hours) did not correlate with CSA or FR values for the dominant hand.
Additionally, in two subjects, an aberrant artery accompanying n. medianus was visualized.
Conclusion:
High-resolution sonographic imaging allows assessment of various morphological properties of median nerve, including its various dimensions and echoic architecture. Furthermore, ultrasound imaging is a very convenient (available, quick, inexpensive and noninvasive) method for examination of peripheral nerve morphology and could thus be used to enhance diagnostic efficiency.