Ultrasound reference values of C5, C6, and C7 brachial plexus roots at the interscalene groove

Objectives: The objective of this study is to estimate the reference values of the brachial plexus roots at the interscalene groove. The physical and demographic characteristics of 59 healthy adult volunteers were studied. The CSA reference values and their correlations with weight, height, age, body mass index (BMI). Methods: Fifty nine (27 males, 32 females) subjects were enrolled in the study. The mean cross sectional area of C5, C6 and C7 nerve roots were obtained. Results: The mean CSA of the brachial plexus roots was as follows: C5 nerve root was 5.1 mm² (range 1.7–11.1 ± 1.9 SD), C6 nerve root CSA 5.8 mm² (range 1.7–12 ± 2.4 SD), and C7 nerve root 6.3 (range 1.6–19.6 ± 3.4 SD). There was a significant statistical difference between both sexes in our study. No statistical significant difference in tissue stiffness between dominant and nondominant hands. No statistical correlation was found between the CSA of the cervical nerve roots and different demographic factors. There was a positive statistical correlation between the CSA of C5 and both C6 and C7 nerve roots. Also positive significant statistical correlation was noted between the CSA of C6 and C7 nerve roots. Conclusion: The CSA reference values of the C5-C7 nerve roots has been determined in asymptomatic individuals and can serve as a reference when studying pathological conditions of these structures.