Correlation of age and the diameter of the cervical nerve roots C5 and C6 during the first 2 years of life analyzed by high‐resolution ultrasound imaging

AIM: To analyze the increase in diameter of the nerve roots C5 and C6 in early childhood. METHODS: The nerve roots of 56 children aged 0 days to 10 years (47 younger than 2 years) were examined by high‐resolution ultrasound imaging. The correlation of diameter and age was statistically tested and a logarithmic regression analysis was performed to develop a logarithmic growth model. RESULTS: The increase in nerve root diameter is greatest during the first 2 years of life and then the growth rate decreases steadily. The relationship between age and diameter follows a logarithmic curve (p < 10(–8)). INTERPRETATION: The main increase in the diameter of the nerve roots happens in the first 2 years of life. Comparing data from a previous study, our data also suggest that the maturation of the proximal part of the median nerve is comparable to the maturation of its distal segments. This suggests a synchronous maturation of the axons and myelin sheath for the whole extent of the nerve, from the radix to its very distal part. WHAT THIS PAPER ADDS: Normative values for the size of the cervical nerve roots C5 and C6; an insight into the maturation of the proximal parts of the peripheral nervous system; and the correlation between age and cervical root diameter.