Reference values for dynamic facial muscle ultrasonography in adults

Ultrasonography can detect structural muscle changes caused by neuromuscular disease, but it has not yet been applied to facial nerve diseases. Quantitative analysis would be the preferred method to determine whether ultrasound findings are within normal limits, but there are no normative data for mimic muscles. The purpose of this study was to provide gender-specific normative ultrasonography data for muscle area, diameter, and contractility for mimic and masticatory muscles in adults.

Bilateral scans of multiple mimic and masticatory muscles were performed at rest and during contraction in 140 volunteers, aged 21-93 years.

Almost all mimic muscles, but not the temporalis muscles, had symmetric size. The muscle sizes showed gender differences and a muscle-specific correlation with body weight, but not with age.

These data provide normative values that can be used in clinical practice.