Sonographic Measurement of Cross-sectional Area of the Median Nerve in Academic Dentists Without Symptoms or Signs of Carpal Tunnel Syndrome

The objective was to evaluate the distribution of the cross-sectional area (CSA) and flattening ratio (FR) of the median nerve (MN) in asymptomatic academic dentists using ultrasonography (US). Fifty academic dentists underwent US of the MN in transverse section at the pisiform bone level and the CSA (mm(2)) and FR were measured bilaterally. A CSA of <10 mm(2) was considered normal. Paired t-test showed no statistical significance between either hand for CSA and FR (P> .05). Two independent t-tests showed significant statistical differences (P= .023) between males and females in the right dominant hand for CSA. Linear correlation analysis showed no significant correlation between CSA and FR for number of years of experience or number of working hours per day in either hand (P>.05). The CSA was abnormal in the right dominant hand in 20 (40%) of the subjects. These male academic dentists were at increased risk of having an enlarged MN without symptoms.